Category Archives: Anatomy

Know your body

The forgotten forearms (Posterior compartment)

Last but not least, the muscles located at the posterior compartment of the forearms.

Superficial posterior compartment

The extensor digitorum muscle helps in the movements of the wrists and the elbows. It extends the phalanges, then the wrist, and finally the elbow. It acts principally on the proximal phalanges. It tends to separate the fingers as it extends them.

Extensor digitorum

Origin:

  1. lateral epicondyle via the CET (common extensor tendon).
  2. antebrachial fascia.

Insertion:

  1. the base of middle phalanx of each of the four fingers (central band).
  2. the base of distal phalanx of each of the four fingers (2 lateral bands).

The extensor digiti minimi is a two joint muscle. It acts as an extensor in both joints. It extends the wrist, which means it moves the back of the hand toward the back of the forearm. It also extends the little finger, which means it straightens the little finger from a fist. When the muscle moves, it forces the little finger to bend and stretch. Sudden or unexpected movement of the finger or trauma may damage the muscle. Traction to keep the little finger from moving is typically recommended to treat the injury. Sprain of this muscle is common in athletes but is not considered to be a serious injury.

Extensor digiti minimi

Origin:

  1. lateral epicondyle via the CET (common extensor tendon).
  2. antebrachial fascia.
  3. the ulnar aspect of extensor digitorum.

Insertion:

  1. the base of middle phalanx of the 5th digit (central band).
  2. the base of distal phalanx of the 5th digit (2 lateral bands).

The extensor carpi ulnaris muscle allows the wrist, or carpus, to extend and bend. It works in conjunction with the flexor carpi ulnaris muscle during the adduction of the wrist, meaning when the wrist bends toward the body’s midline. However, it is the only muscle responsible for ulnar deviation. This refers to the movement of the hand sideways in the direction of the pinky. The extensor carpi ulnaris muscle is the primary muscle used when you accelerate your motorcycle.

Extensor carpi ulnaris

Origin:

  1. 1st head – lateral epicondyle via the CET (common extensor tendon).
  2. 2nd head – the posterior body of the ulna.
  3. antebrachial fascia.

Insertion:

medial side of the base of the 5th metacarpal.

A common injury to the extensor carpi ulnaris is tennis elbow. This injury occurs in people that participate in activities requiring repetitive arm, elbow, and wrist, especially when they are tightly gripping an object. Some symptoms include pain when shaking hands or when squeezing/gripping an object. The pain worsens when a person moves their wrist with force. The pain intensifies because the extensor carpi ulnaris has an injury near the elbow area and as a person moves their arm, the muscle contracts, thus causing it to move over the lateral epicondyle of the humerus. This causes irritation to the already existing injury.

The brachioradialis flexes the forearm at the elbow. It enables flexion of the elbow joint. The muscle also assists with pronation and supination of the forearm. These two movements allow the forearm and hand to turn so that the palm faces up or down. The arms are the only part of the body with this ability. The muscle is used to stabilize the elbow during rapid flexion and extension while in a mid position, such as in hammering.

Brachioradialis

Origin:

  1. the upper lateral supracondylar ridge of the humerus (between the triceps and brachialis muscles).
  2. the lateral intermuscular septum of the humerus.

Insertion:

  1. the superior aspect of the styloid process of the radius.
  2. the lateral side of the distal 1/2 to 1/3 of the radius.
  3. antebrachial fascia.

The extensor carpi radialis longus is a long muscle that connects the outside of the elbow to the bone at the base of the first finger. It extends the wrist and abducts the hand.

Extensor carpi radialis longus

Origin:

  1. lower lateral supracondylar ridge (below the brachioradialis).
  2. the lateral intermuscular septum of the humerus.

Insertion:

the base of 2nd metacarpal.

The extensor carpi radialis brevis muscle aids in moving the hand. Specifically, it abducts and extends the hand at the wrist joint. It is an extensor, and an abductor of the hand at the wrist joint. That is, it serves to manipulate the wrist so that the hand moves away from the palm and towards the thumb.

Extensor carpi radialis brevis

Origin:

  1. lateral epicondyle via the CET (common extensor tendon).
  2. radial collateral ligament.
  3. antebrachial fascia.

Insertion:

base of 3rd metacarpal.

Deep posterior compartment

Supinator consists of two planes of fibers, between which the deep branch of the radial nerve lies. Its function is to supinate the forearm. Supinator always acts together with biceps, except when the elbow joint is extended.

Supinator

Origin:

  1. lateral epicondyle of humerus.
  2. supinator crest of ulna.
  3. radial collateral ligament.
  4. annular ligament.
  5. antebrachial fascia.

Insertion:

the proximal portion of the anteriorlateral surface of the radius

The extensor indicis extends the index finger, and by its continued action assists in extending the wrist and the mid carpal joints. Because the index finger and little finger have separate extensors, these fingers can be moved more independently than the other fingers.

Extensor indicis

Origin:

  1. the posterior surface of ulna (distal to extensor pollicis longus).
  2. interosseous membrane.
  3. antebrachial fascia.

Insertion:

the base of the middle and distal phalanx of the index finger

The abductor pollicis longus muscle is one of three muscles in the forearm that facilitate the movements of the thumb. The others are the extensor pollicis brevis and extensor pollicis longus. These three muscles, along with the extensor indicis, make up the group of muscles called the deep extensors.The abductor pollicis longus lies immediately below the supinator and is sometimes united with it. The chief action of abductor pollicis longus is to abduct the thumb. It also assists in extending and rotating the thumb.

Abductor pollicis longus muscle

Origin:

  1. posterior surfaces of ulna and radius.
  2. interosseous membrane.
  3. antebrachial fascia.

Insertion:

lateral aspect of base of 1st metacarpal

The extensor pollicis brevis muscle is located on the dorsal side of the forearm. In a close relationship to the abductor pollicis longus, the extensor pollicis brevis both extends and abducts the thumb.

Abductor pollicis brevis muscle

Origin:

  1. posterior surfaces of radius (below abductor pollicis longus).
  2. interosseous membrane.
  3. antebrachial fascia.

Insertion:

the base of proximal phalanx of thumb (often a slip inserts into extensor pollicis longus tendon)

The extensor pollicis longus extends the terminal phalanx of the thumb. When moving the thumb, the muscle uses the radial tubercle as a pulley.

Extensor pollicis longus

Origin:

  1. posterior surface of ulna.
  2. interosseous membrane.
  3. antebrachial fascia.

Insertion:

distal phalanx of the thumb.

The forgotten forearms (Anterior compartment)

The lower “arm” is called the forearm. The forearm contains many muscles, including the flexors and extensors of the digits, a flexor of the elbow (brachioradialis), and pronators and supinators that turn the hand to face down or upwards, respectively. In cross-section, the forearm can be divided into two fascial compartments. The posterior compartment contains the extensors of the hands, which are supplied by the radial nerve. The anterior compartment contains the flexors, and is mainly supplied by the median nerve. Let´s focus on this one.

Superficial anterior compartment

Pronator teres pronates the forearm, turning the hand posteriorly. If the elbow is flexed to a right angle, then pronator teres will turn the hand so that the palm faces inferiorly. It is assisted in this action by pronator quadratus.

It also weakly flexes the elbow, or assists in flexion at the elbow when there is strong resistance.

Pronator teres syndrome is one cause of wrist pain. It is a type of neurogenic pain.

  • Patients with the pronator teres syndrome have numbness in median nerve distribution with repetitive pronation/supination of the forearm, not flexion and extension of the elbow.
  • Early fatigue of the forearm muscles is seen with repetitive stressful motion, especially pronation.
  • EMG may show only mildly reduced conduction velocities.
  • despite their anatomic proximity, patients with pronator teres syndrome do not have a higher incidence of AIN syndrome.

Pronator teres

Origin:

  1. Humeral head:

A. upper portion of medial epicondyle via the CFT (common flexor tendon).

B. medial brachial intermuscular septum.

2. Ulnar head – coronoid process of ulna.

3. Antebrachial fascia.

Insertion:

Lateral aspect of radius at the middle of the shaft (pronator tuberosity).

Flexor carpi radialis is a muscle of the human forearm that acts to flex and (radial) abduct the hand. It is a superficial muscle that becomes very visible as the wrist comes into flexion. The flexor carpi radialis muscle is located close to the palm side of the arm, which allows it to bend the wrist on its side. This helps to reduce the angle between the forearm and the thumb. The wrist remains straight and does not extend or bend backwards.

Flexor carpi radialis

Origin:

  1. Medial epicondyle via the CFT (common flexor tendon).
  2. Antebrachial fascia.

Insertion:

Base of the 2nd and sometimes 3rd metacarpals

Palmaris longus serves no apparent function in humans.For this reason, it is actually very popular with reconstructive surgeons because they can “harvest” the tissue or the tendon and use it to rebuild other useful muscles. What is even more interesting is the fact that the muscle is completely or partially absent in about 14 percent of the population.

Palmaris longus

 Origin:

  1. Medial epicondyle via the CFT (common flexor tendon).
  2. Antebrachial fascia.

Insertion:

  1. Central portion of the flexor retinaculum.
  2. Superficial portion of the palmar aponeurosis.

The flexor carpi ulnaris muscle works in tandem with the extensor carpi ulnaris. These muscles flex the wrist and adduct it (move it laterally in the direction of ulnar).

Flexor carpi ulnaris

Origin:

  1. Humeral head – medial epicondyle via the CFT (common flexor tendon).
  2. Ulnar head:
  • Medial aspect of olecranon.
  • Proximal 3/5 of dorsal ulnar shaft.
  • Antebrachial fascia.

Insertion:

  1. Pisiform & hamate bones (via the pisohamate ligament).
  2. Base of the 5th metacarpal (via the pisometacarpal ligament).

The flexor digitorum superficialis is an extrinsic muscle that allows the four medial fingers of the hand to flex. It flexes the middle phalanges of the fingers at the proximal interphalangeal joints, however under continued action it also flexes the metacarpophalangeal joints and wrist joint. The secondary role of the muscle is to flex the metacarpophalangeal joints. These are located between the proximal phalanges and the metacarpal bones of the palm.

Flexor digitorum superficialis

Origin:

  1. Humeral-ulnar head:
  • Medial epicondyle via the CFT (common flexor tendon).
  • Medial boarder of base of coronoid process of ulna.
  • Medial (ulnar) collateral ligament.
  • Antebrachial fascia.

2. Radial head: oblique line of radius along its upper anterior boarder.

Insertion:

Both sides of the base of each middle phalanx of the 4 fingers

Deep anterior compartment

The pronator quadratus is a muscle that is near the lower part of the radius. It is the only muscle attached only to the radius at one end and the ulna at the other.

Its function is to rotate the forearm and keep the proper distance and rotation between the ulna and radius. It is also used to turn the wrist and palm of the hand. When pronator quadratus contracts, it pulls the lateral side of the radius towards the ulna, thus pronating the hand. Its deep fibers serve to keep the two bones in the forearm bound together.

Pronator quadratus

Origin:

Distal 1/4 anteriomedial surface of ulna.

Insertion:

Distal 1/4 anteriolateral surface of radius.

The flexor digitorum profundus belly is located in the forearm. However, it is considered a hand muscle because it is primarily used for hand functionality. The muscle’s long tendons extend over the wrist and the metacarpals of the hand.

It is a flexor of the wrist and helps flex the fingers.

Flexor digitorum profundus 2

Origin:

  1. Anterior & medial surface of upper 3/4 ulna.
  2. Adjacent interosseous membrane.

Insertion:

Distal phalanx of medial 4 digits (through FDS tunnel).

The flexor pollicis longus muscle is located in the lower half of the arm, from the elbow down. It is an anatomical part that is unique to humans.

The flexor pollicis longus is a flexor of the phalanges of the thumb; when the thumb is fixed, it assists by flexing the wrist.

Flexor pollicis longus

Origin:

  1. Middle anterior surface of the radius.
  2. Interosseous membrane.
  3. (may also originate from lateral boarder of coronoid process.
  4. or medial epicondyle).

Insertion:

Palmar aspect of base of the distal phalanx of thumb (deep to flexor retinaculum).

Bigger arms!

Everyone wants bigger arms, but there’s no such thing as a magical workout you can do to get them.

Arms

Let´s see the most important muscles:

The Coracobrachialis is a long, slender muscle of the shoulder joint.

The contraction of the coracobrachialis leads to two movements at the shoulder joint. On one hand, it bends the arm (flexion), and on the other hand, it pulls the arm towards the trunk (adduction). To a smaller extent, it also turns the humerus inwards (inward rotation). Another important function is the stabilization of the humeral head within the shoulder joint, especially when the arm is hanging freely straight down.

 

Origin:

Coracoid process of the scapula.

Insertion:

The medial shaft of the humerus at about its middle.

The overuse of the coracobrachialis can lead to stiffening of the muscle. Common causes of injury include chest workouts or activities that require pressing the arm very tight towards the body, e.g. work on the rings in gymnastics. Symptoms of overuse or injury: pain in the arm and shoulder, radiating down to the back of the hand.

Pain and symptoms associated with the Coracobrachialis muscle
– Pain in the back of the upper arm
– Pain in the front of the upper arm around the shoulder joint
– Pain in the back of the lower arm
– Pain in the back of the hand extending down into the middle finger
– Difficulty bending the elbow
– Pain when putting arm and hand behind the head and back
– Pain when raising arm overhead
– Occasionally numbness in the upper arm that can extend into the forearm and back of the hand
Activities that cause coracobrachialis pain and symptoms
– Push ups
– Rock or rope climbing
– Throwing a ball
– Golf
– Tennis
– Lifting heavy weights with outstretched arms and palms facing up

The Biceps brachii, commonly known as the biceps, is a two-headed muscle that lies on the upper arm between the shoulder and the elbow. The Biceps muscle is actually two separate bundles of muscles (heads). The two heads of the Biceps vary in length and as a result, are called the Short and the Long Biceps heads.

 

Origin:

  1. Long head- supraglenoid tubercle and glenohumeral labrum.
  2. Short head- tip of the coracoid process of the scapula.

Insertion:

  1. Radial tuberosity.
  2. Bicipital aponeurosis.

The biceps works across three joints.

Proximal radioulnar joint (upper forearm): It functions primarily as a powerful supinator of the forearm (turns the palm upwards). This action, which is aided by the supinator muscle requires the elbow to be at least partially flexed.

Humeroulnar joint (elbow): It also functions as an important flexor of the forearm, particularly when the forearm is supinated. This action is performed when lifting an object, such as a bag of groceries. When the forearm is in pronation (the palm faces the ground), the brachialis, brachioradialis, and supinator function to flex the forearm, with minimal contribution from the biceps brachii.

Glenohumeral joint (shoulder): TIt weakly assists in forward flexion of the shoulder joint (bringing the arm forward and upwards). It also contributes to abduction (bringing the arm out to the side) when the arm is externally (or laterally) rotated. The short head also assists with horizontal adduction (bringing the arm across the body) when the arm is internally (or medially) rotated. Finally, the short head, due to its attachment to the scapula (or shoulder blade), assists with stabilization of the shoulder joint when a heavy weight is carried in the arm.

Pain and symptoms associated with the Biceps Brachii muscles
– Pain in the front of the shoulder
– Pain in the crease of the elbow
– Weakness in the arm
– Difficulty straightening arm with palm facing down
– Pain at the top of the back of the shoulder (between the neck and shoulder joint)
– Unless there is a recent injury to the biceps muscle, pain is seldom felt directly in the muscle
Activities that cause biceps brachii pain and symptoms
– Lifting heavy objects
– Chin ups, Pull ups
– Playing the violin
– Repetitive twisting of the arm with the elbow bent, ie. using a screwdriver
– The most important function of the biceps brachii is it allows us to carry objects and not pull the shoulder joint apart.
– Violinists and cellists often have problems and pain in the biceps.

The brachialis is a muscle in the upper arm that flexes the elbow joint. It lies deeper than the biceps brachii and is a synergist that assists the biceps brachii in flexing at the elbow.

 

Origin:

  1. Lower 1/2 of anterior humerus.
  2. Both intermuscular septa.

Insertion:

  1. Ulnar tuberosity.
  2. Coronoid process of ulna slightly.

Its primary action is to flex the forearm muscles at the elbow. Due to its high contractile strength, the branchialis makes many arm and elbow movements possible. Such movements are important for the activities of daily life. Because movements involving the arms and elbows are almost always continuous, injuries to the brachialis muscle are quite common.

Pain and symptoms associated with the Brachialis muscle
– Pain at the front and /or back of the base of the thumb
– Constant aching and/or tightness in the outside of the upper arm near the elbow
– Numbness or tingling in the forearm and thumb
– Difficulty bending the elbow
Activities that cause brachialis pain and symptoms
– Lifting heavy objects with a bent elbow
– Picking up children
– Holding up heavy tools
– Working at the computer
– Chin ups
– Playing the oboe, clarinet, and saxophone

The Triceps Brachii muscles are located on the back of the humerus and more commonly referred to as the triceps. The triceps muscles have three muscle heads: Lateral, Medial and Long head.

 

Origin:

  1. Long head: infraglenoid tubercle of the scapula.
  2. Lateral head: upper half of the posterior surface of the shaft of the humerus, and the upper part of the lateral intermuscular septum.
  3. Medial head: posterior shaft of humerus, distal to radial groove and both the medial and lateral intermuscular septum (deep to the long & lateral heads).

Insertion:

  1. Posterior surface of the olecranon process of the ulna.
  2. Deep fascia of the antebrachium.

Primarily responsible for the extension of the elbow joint (straightening of the arm). It can also fixate the elbow joint when the forearm and hand are used for fine movements, e.g., when writing. The lateral head is used for movements requiring occasional high-intensity force, while the medial fascicle enables more precise, low-force movements.

With its origin on the scapula, the long head also acts on the shoulder joint and is also involved in retroversion and adduction of the arm.

Pain and symptoms associated with the Triceps Brachii muscle
– Pain in the back of the shoulder
– Pain at the base of the neck
– Pain on the outside of the elbow
– Pain throughout the back of the elbow
– Feeling of weakness in the elbow
– Pain in the back of the upper arm
– Can make elbow hypersensitive
– Occasionally pain and/or burning down into the fourth and fifth fingers
– Difficulty straightening and bending the elbow
– Pain is usually dull and aching, rarely is the pain sharp or stabbing
Activities that cause triceps brachii muscle pain and symptoms
– Tennis
– Golfing
– Swinging a baseball bat
– Repetitive pushing downward action
– Forcefully holding something down.

The anconeus muscle (or anconaeus/anconæus) is a small muscle on the posterior aspect of the elbow joint.

Anconeus

Origin:

Posterior surface of the lateral epicondyle of the humerus.

Insertion:

Lateral aspect of olecranon extending to the lateral part of ulnar body.

It assists in extension of the elbow, where the triceps brachii is the principal agonist, and supports the elbow in full extension. It also prevents the elbow joint capsule being pinched in the olecranon fossa during extension of the elbow. Anconeus also abducts the ulna and stabilizes the elbow joint. Anconeus serves to make minute movements with the radius on the ulna. In making slight abduction of the ulna, it allows any finger to be used as a axis of rotation of the forearm.

Activities That Cause Pain and Symptoms of the Anconeus

– Forced and repetitive gripping of a large and/or wide object
– Extreme sudden hard extension (straightening) of the elbow
– Pushing a door closed
– Rotating arm to shake hands
– Golfing (non-dominate arm)
– Tennis (dominant arm)
– Rowing motions

Shoulder

When we talk about the shoulder we usually mean the deltoid. There are more important muscles around your shoulder joint than deltoid, like the rotator cuff muscles, and you should take care of them to avoid injuries.

The Deltoid muscle is the muscle forming the rounded contour of the shoulder. It is divided into three portions, anterior, lateral and posterior, with the fibers having different roles due to their orientation.

Deltoid

  1. The anterior fibers are involved in shoulder abduction when the shoulder is externally rotated. It also works with the subscapularis, pecs and lats to internally (medially) rotate the humerus.
  2. The posterior fibers are strongly involved in transverse extension particularly as the latissimus dorsi is very weak in strict transverse extension. The infraspinatus and teres minor, also work with the posterior deltoid as external rotators, antagonists to strong internal rotators like the pecs and lats. The posterior deltoid is also the primary shoulder hyperextensor, more so than the long head of the triceps which also assists in this function.
  3. The lateral fibers perform the shoulder abduction when it is internally rotated, and perform shoulder transverse abduction when the shoulder is externally rotated.

Origin:

  1. Lateral, anterior 1/3 of the distal clavicle.
  2. Lateral boarder of the acromion.
  3. Scapular spine.

Insertion:

Deltoid tuberosity of the humerus.

Pain and symptoms associated with the Deltoid muscle

– Pain over the tip of the shoulder going down the upper arm
– Shoulder weakness
– Pain in the shoulder area when lifting
– Pain in the shoulder area when holding objects up and in front of the body
– Pain decreases when arm and shoulder are at rest

Pain around the shoulder area caused by the deltoids muscles will subside when resting. If the pain in the deltoid area is continuous even at rest, chances are the source of the pain is being caused by other muscles in the neck, shoulder, upper back, and/or chest.

Activities that cause deltoid pain and symptoms

– Swimming
– Skiing
– Weight-lifting
– Throwing a ball; baseball, softball, football
– Holding heavy tools up
– Picking up and carrying children
– Typing when the keyboard is set up too high

The Teres major is a medial rotator and adductor of the humerus and assists the latissimus dorsi in drawing the previously raised humerus downward and backward (extension, but not hyperextension). It also helps stabilize the humeral head in the glenoid cavity. It is only functional when the Rhomboids fix the scapula. This muscle mainly helps latissimus dorsi.

Origin:

Inferior, lateral margin of the scapula.

Insertion:

Crest of lesser tubercle (just medial to the insertion of latissimus dorsi)

Pain and symptoms associated with the Teres Major muscle

– Pain in the back of the upper arm when reaching forward and up
– Sharp pain in the back of the shoulder with aching sensation in the upper arm when resting elbows on a table.
– Pain in the back of the arm that skips the elbow and continues down to the back of the forearm.

Activities that cause teres major muscle pain and symptoms

– Rowing
– Throwing or pitching a ball
– Swimming
– Chopping wood
– Driving
– Exercise that requires pulling up (chin-up) or pushing down (push-ups) with the arms, or reaching forward or overhead repetitiously

The Supraspinatus muscle is one of the four muscles which make up the rotator cuff. Its main function is to stabilize the upper arm by holding the head of the humerus in position. It is important in throwing motions to control any forward motion of the head of the humerus. Contraction of the supraspinatus muscle leads to the abduction of the arm at the shoulder joint. It is the main agonist muscle for this movement during the first 10-15 degrees of its arc. Beyond 30 degrees, the deltoid muscle becomes increasingly more effective at abducting the arm and becomes the main propagator of this action.

Origin:

  1. Supraspinous fossa.
  2. Muscle fascia.

Insertion:

Uppermost of three facets of the greater tubercle of the humerus.

Pain and symptoms associated with the Supraspinatus muscle

– Deep ache over the outside of the shoulder area which continues during rest
– Pain down the outside of the arm, occasionally extending down into the wrist
– Can cause clicking or popping in the shoulder joint
– Concentrated pain toward the outside of the elbow
– Pain when lifting the arm overhead
– Difficulty and shoulder pain while shaving the face or combing hair

Activities that cause supraspinatus muscle pain and symptoms

– Carrying heavy objects with the arm hanging down ie. suitcase, a bucket of paint, etc.
– Working with arms outstretched in front of the body and /or overhead (painting, working at the computer, driving for long periods)
– Tennis
– Golf

The Infraspinatus muscle is another of the four rotator cuff muscles crossing the shoulder joint and is commonly injured. It is the main external rotator of the shoulder joint. When the arm is fixed, it abducts the inferior angle of the scapula. Its synergists are teres minor and the deltoid. The infraspinatus and teres minor rotate the head of the humerus outward (external, or lateral, rotation); they also assist in carrying the arm backward. Also, reinforces the capsule of the shoulder joint.

Origin:

  1. Infraspinous fossa.
  2. Muscle fascia.

Insertion:

The middle facet of greater tubercle of the humerus.

Pain and symptoms associated with the Infraspinatus muscle

– Pain deep in the front of the shoulder
– Pain going down the front and outside of the arm, sometimes going down into the hand
– Pain going up the back of the neck to the base of the skull
– Pain in the upper back at the inside edge of the shoulder blade
– Weakness and stiffness in the shoulder and arm
– Difficulty reaching the arm behind the body and reaching into a back hip pocket

Activities that cause infraspinatus pain and symptoms

– Keeping the arms overhead for extended periods of time
– Painting overhead
– Keeping the arms extended in front of the body for extended periods of time
– Driving with hands on top of the steering wheel
– Keyboarding and using the mouse on the computer
– Swimmers
– Sports throwing a ball or swinging at a ball
– Tennis
– Baseball
– Football

The subscapularis rotates the head of the humerus medially (internal rotation); when the arm is raised, it draws the humerus forward and downward. It is a powerful defense to the front of the shoulder-joint, preventing displacement of the head of the humerus.

Origin:

Subscapular fossa.

Insertion:

Lesser tubercle of the humerus.

Pain and symptoms associated with the Subscapularis muscle

– Severe pain deep in the back of the shoulder
– Pain in the back of the upper arm
– Pain over the shoulder blade area
– Pain can extend down the back of the arm
– Persistent aching in the wrist with extreme tenderness in the back of the wrist
– Occasionally an extremely tender spot on the front of the shoulder

Activities that cause subscapularis pain and symptoms

– Pitching a baseball
– Tennis
– Swimming
– Tossing heavy objects
– Playing the violin, guitar, banjo
– Falling and landing on your side
– Sleeping on one side
– Immobilization of the arm for long periods (casted arm)

The Teres minor is a narrow, elongated muscle of the rotator cuff.

The Teres minor and the infraspinatus attach to the head of the humerus; they help hold the humeral head in the glenoid cavity of the scapula. They work in tandem with the posterior deltoid to externally (laterally) rotate the humerus, as well as perform transverse abduction, extension, and transverse extension.

Origin:

The middle half of the scapula’s lateral margin.

Insertion:

Lowest of three facets of the greater tubercle of the humerus.

Pain and symptoms associated with the Teres Minor muscle

– Pain toward the back of the upper arm
– Numbness or tingling without pain or aches in the fourth and fifth fingers

Activities that cause teres minor pain and symptoms

– Bringing the arm back with force
– Pitching a baseball
– Rowing, Kayaking
– Holding arms above head for extended periods
– Holding arms out in front of the body for extended periods of time
– Bracing your arms either in front of the body to avoid a fall or overhead impact (something falling from above)

There are two types of rotator cuff injuries:

  1. Acute tears occur as a result of a sudden movement. This might include throwing a powerful pitch, holding a fast moving rope during water sports, falling over onto an outstretched hand at speed, or making a sudden thrust with the paddle in kayaking.
  2. A chronic tear develops over a period of time. They usually occur at or near the tendon, as a result of the tendon rubbing against the underlying bone.

Rotator cuff tear

Please, be careful 🙂

“Lats” & friends

We usually forget that lats belong to another muscle group, the superficial back muscles. They originate from the vertebral column and attach to the bones of the shoulder – the clavicle, scapula, and humerus. All these muscles are therefore associated with movements of the upper limb.

The muscles in this group are the latissimus dorsi, trapezius, levator scapulae and the rhomboids.

The latissimus dorsi is the larger, flat, dorsolateral muscle on the trunk, posterior to the arm, and partly covered by the trapezius on its median dorsal region.

Origin:

  1. Spinous process of T7-L5.
  2. Upper 2-3 sacral segments.
  3. Iliac crest.
  4. Lower 3 or 4 ribs.

Insertion:

Lateral lip of the intertubercular groove.

It is responsible for extension, adduction, horizontal abduction, flexion from an extended position, and (medial) internal rotation of the shoulder joint. It also has a synergistic role in extension and lateral flexion of the lumbar spine.

Pain and symptoms associated with the Latissimus Dorsi muscle
– Pain is felt in the mid-back especially below the bottom of the shoulder blade.
– Pain is felt in the front of the shoulder.
– Pain in the side and or mid-back similar to a side stitch.
– Numbness, tingling and/or aching that extends down the arm to the little finger and often the ring finger.
– Pain while reaching forward with the arms
– Pain when lifting arms overhead
– Can contribute to breathing difficulty.
– Pain does not worsen with activity nor does it ease at rest, it is steady and constant.
Activities that can cause latissimus dorsi pain
– Activities that require continuously or repeatedly raising the shoulders
– Gymnastics
– Rowing
– Throwing or pitching a ball
– Swimming
– Swinging a baseball bat
– Swinging a tennis racket
– Shoveling dirt or snow
– Chopping wood
– Exercise that requires pulling up (chin up) or pushing down (push-ups) with the arms
– Reaching forward or overhead repetitiously

The trapezius is a broad, flat and triangular muscle. The muscles on each side form a trapezoid shape. It is the most superficial of all the back muscles.

 

Origin:

  1. External occipital protuberance.
  2. Along the medial sides of the superior nuchal line.
  3. Ligamentum nuchae (surrounding the cervical spinous processes).
  4. Spinous processes of C1-T12.

Insertion:

  1. Posterior, lateral 1/3 of clavicle.
  2. Acromion.
  3. The superior spine of the scapula.

It has three functional regions:

  1. Superior (descending part), which supports the weight of the arm.
  2. Intermediate (transverse part), which retracts the scapulae.
  3. Inferior (ascending part), which medially rotates and depresses the scapulae.

Contraction of the trapezius muscle can have two effects:

  1. Movement of the scapulae when the spinal origins are stable.
  2. Movement of the spine when the scapulae are stable. Its main function is to stabilize and move the scapula.
Pain and symptoms associated with the Trapezius muscle
– Headache in the temple area
– Pain in the jaw that travels down into the neck and over behind the ear
– Pain behind one eye
– Tension headache
– Contributes to dizziness
– Pain at the base of the skull
– Stiff neck
– Ache or burning sensation in the middle of the back
– Pain or tingling during raising or lowering the arms
Activities that cause pain and symptoms in the trapezius
– Whiplash
– Lifting heavy objects
– Working with your arms out in front of you (computer, playing the piano, driving)
– Keeping your shoulders rolled forward or pulled up
– Carrying a heavy purse or backpack on one shoulder
– Large breasts

The levator scapulae is a small strap-like muscle. It elevates the scapula.

Origin:

Transverse processes of C1-C3 or C4.

Insertion:

The superior angle of scapula toward the scapular spine.

Pain and symptoms associated with the Levator Scapulae muscle
– Pain at the slope of the neck and shoulder
– Stiff neck, difficulty turning head to look over the shoulder
– Headaches at the base of the skull
– Occasionally pain from the top of the shoulder blade extending to the middle of the shoulder blade
Activities that cause pain or symptoms of the levator scapulae muscle
– Keeping head turned to one side ie. Sleeping on stomach, holding phone to ear with shoulder
– Sleeping without proper head support
– Acute upper respiratory infection will cause the levator scapulae to shorten and become stiff and painful
– Painting overhead for extended periods
– Carrying heavy backpacks or purses
– Whiplash
– Forward head posture

There are two rhomboid muscles, major and minor. The rhomboid major helps to hold the scapula (and thus the upper limb) onto the ribcage. Together with the rhomboid major, the rhomboid minor retracts the scapula when trapezius is contracted. Acting as an antagonist to the trapezius, the rhomboid major and minor elevate the scapula medially and upward, working in tandem with the levator scapulae muscle to rotate the scapulae downward. While other shoulder muscles are active, the rhomboid major and minor stabilize the scapula.

Rhomboid major:

Origin:

  1. Spinous processes of T2-T5.
  2. Supraspinous ligament.

Insertion:

Medial scapula from the scapular spine to the inferior angle

Rhomboid minor:

Origin:

  1. Spinous process of C7 & T1.
  2. Ligamentum nuchae.
  3. Supraspinous ligament.

Insertion:

Medial margin of the scapula at the medial angle

Pain and symptoms associated with the Rhomboid Major and Minor muscles
– Pain along the inside of the shoulder blade especially noticeable at rest.
– Popping and/or grinding noise when moving the shoulder blade
– Inability to straighten the upper body out of a slumped position
Activities that can cause rhomboid muscle pain
– Activities that require continuously or repeatedly raising the shoulders
– Hanging wallpaper
– Rowing
– Throwing a ball
– Pull Ups
– Extended work at the computer
– Military posture: standing with extremely straight posture with shoulders pulled back, chest thrust forward.

Pecs

We usually call our pectoral muscles “pecs”.  The first thing we need to know is that pectoral muscles are a group of muscles.

The pectoralis major makes up the bulk of the chest muscles in the male and lies under the breast in the female.

 

Origin:

  1. Medial 1/3 of the clavicle.
  2. Anterior aspect of manubrium & length of the body of the sternum.
  3. Cartilaginous attachments of upper 6 ribs.
  4. External oblique’s aponeurosis.

Insertion:

  1. Lateral lip of bicipital groove to the crest of the greater tubercle.
  2. Clavicular fibers insert more distally; sternal fibers more proximally.

It performs four actions:

  1. Flexion of the humerus, as in throwing a ball side-arm, and in lifting a child.
  2. Adducts the humerus, as when flapping the arms.
  3. Rotates the humerus medially, as occurs when arm-wrestling.
  4. Keeps the arm attached to the trunk of the body.
Pain and symptoms associated with the Pectoralis Major muscle
– Chest pain
– Pain in the front of the shoulder
– Pain in the inner arm, inner elbow traveling down to the into the middle and ring fingers
– Breast pain
– Upper back pain between and around the shoulder blades
– Pain when trying to reach behind the body
– Rounded shoulder posture
– Contributor to forward head posture
Activities that cause pain and symptoms of the pectoralis major muscle
– Lifting heavy objects
– Working with your arms out in front of you (computer)
– Driving and horseback riding: both require you to hold your arms up and in front of your body
– Keeping your shoulders rolled forward or pulled up
– Slouching
– Carrying a heavy purse or backpack on one shoulder
– Large breasts

The pectoralis minor is a thin, triangular muscle, situated at the upper part of the chest, beneath the pectoralis major. The pectoralis minor depresses the point of the shoulder, drawing the scapula inferior, towards the thorax, and throwing its inferior angle posteriorly.

 

Origin:

The outer surface of ribs 2-5 or 3-5 or 6.

Insertion:

Medial aspect of the coracoid process of the scapula.

Pain and symptoms associated with the Pectoralis Minor muscle
– Chest pain
– Burning and stabbing like pain in the pectoral (chest) area
– Pain in the front of the shoulder
– Pain in the inner arm, inner elbow traveling down to the into the fourth and fifth fingers
– Numbness in the inside of the forearm, wrist, hand and fingers
– Difficulty reaching forward and up
– Pain in the upper back between the shoulder blades
– Pain when reaching behind the body
– Rounded shoulder posture
Activities that cause pectoralis minor pain and symptoms
– Lifting heavy objects
– Pushing things away from the body
– Push ups
– Lifting objects with arms straight in front of the body
– Working with your arms out in front of you (computer)
– Keeping your shoulders rolled forward or pulled up
– Carrying a heavy purse or backpack on one shoulder
– Hyperventilation, difficulty breathing
– Chronic cough
– Under-wire bras
– Large breasts
– Whiplash

The subclavius is a small triangular muscle, placed between the clavicle and the first rib. Along with the pectoralis major and pectoralis minor muscles, the subclavius muscle makes up the anterior wall of the axilla.

Subclavius

Origin:

First rib about the junction of bone and cartilage.

Insertion:

The lower surface of the clavicle.

The subclavius depresses the shoulder, carrying it downward and forward. It draws the clavicle inferiorly as well as anteriorly. Also, protects the underlying brachial plexus and subclavian vessels from a broken clavicle (the most frequently broken long bone).

Pain and symptoms associated with the subclavius muscle

– Pain below the collarbone
– Pain in the upper arm
– Sends pain down the forearm into the thumb, forefinger, and middle finger
– A reliable indicator of subclavius muscle dysfunction is a pain on the outside of the upper arm that skips over the elbow then extends into the forearm. Pain can also extend to the thumb, index, and middle finger while skipping over the wrist.
– The muscle can tighten restricting circulation to the arm and hand causing tingling and numbness

Activities that cause subclavius pain and symptoms

– Lifting heavy objects
– Working with your arms out in front of you (computer, driving)
– Keeping your shoulders rolled forward
– Sleeping on your side with your arm above your head
– Broken clavicle

 

The serratus anterior is found more laterally in the chest and, forms the medial wall of the axilla.

Serratus anterior

Origin:

Fleshy slips from the outer surface of upper 8 or 9 ribs.

Insertion:

The costal aspect of medial margin of the scapula.

The main action of the serratus anterior is to rotate the scapula, allowing the arm to be raised over 90 degrees. It also holds the scapula against the rib cage – this is particularly useful when upper limb reaches anteriorly (e.g punching).

Pain and symptoms associated with the Serratus anterior

– Pain on the side of the chest toward the middle of the ribcage
– Pain down the arm to the fourth and fifth fingers
– Pain below the shoulder blade
– Difficulty breathing
– Inability to take a deep breath
– Sharp pain in the side (side stitch)
– Pain and difficulty reaching behind the body
– Pain and difficulty when pulling shoulders back
– Sensitivity in and around the area of the breast

Activities that cause serratus anterior pain and symptoms

– Swimming
– Tennis
– Chin ups, Push ups
– Weightlifting
– Gymnastics
– Hyperventilation
– Severe coughing

Six-pack

Six pack has 54M results on Google. Not everybody but a lot of people desires a “six-pack”, others simply need to strength their middle section to relief or avoid pain or bad postures.

AbdomenThe transverse abdominal muscle (TVA) is a very important core muscle which is vital in maintaining good posture. It helps to compress the ribs and viscera, providing thoracic and pelvic stability.

The transverse abdominal and the segmental stabilizers of the spine work in tandem.

Without a stable spine, the nervous system fails to recruit the muscles in the extremities, and functional movements cannot be performed.

The TVA is vital to back and core health. Also has the effect of pulling in the abdomen. Training only the rectus abdominis muscle will not and can not give one a “flat” belly. This goal is achieved only through training the TVA.

Recently, the transverse abdominal muscle has become the subject of debate between kinesiologists, strength trainers, and physical therapists. The two positions on the muscle are:

  1. The muscle is effective and capable of bracing the human core during heavy lifts.
  2. It is not.

Anyway, how to do a stomach vacuum:

Origin:

  1. Front of the iliac crest.
  2. Inguinal ligament.
  3. Costal cartilages of the lower 6 ribs.
  4. Thoracolumbar fascia.

Insertion:

Linea alba.

Rectus Abdominis is the most superficial of the abdominal muscles. It is this muscle which forms the six-pack shape! It is a paired muscle running vertically on each side of the anterior wall of the abdomen. There are two parallel muscles, separated by a midline band of connective tissue called the linea alba.

Origin:

  1. Crest of the pubis.
  2. Pubic symphesis.

Insertion:

  1. Xiphoid process (base of the sternum).
  2. 5th,6th and 7th costal cartilages.

The six-pack flexes the lumbar spine, as when doing a so-called “crunch” sit up. The rib cage is brought up to where the pelvis is when the pelvis is fixed:

or the pelvis can be brought towards the rib cage (posterior pelvic tilt) when the rib cage is fixed, such as:

The Rectus Abdominis assists with breathing and plays an important role in respiration when forcefully exhaling. It also helps in creating intra-abdominal pressure, such as when exercising or lifting heavy weights.

Pain and symptoms associated with the Rectus Abdominis muscle
– Pain that runs horizontal across the mid back under the shoulder blade
– Pain that runs horizontal across the low back
– Pain around the sternum between the breasts (not shown)
– Pain in the low abdomen
– Feeling bloated
– Heartburn and indigestion
– Testicle pain
– Pain in the pelvic area
Activities that cause rectus abdominis pain and symptoms
– Over exercising muscles (sit-ups and leg-ups)
– Shallow breathing
– Chronic coughing
– Sitting for long periods of time
– Sitting in a twisted position
– Childbirth
– Abdominal surgery
– Scars from abdominal surgery
– Chronic Constipation
– Carrying a heavy backpack

The external oblique is situated on the lateral and anterior parts of the abdomen. It is broad, thin, and irregularly quadrilateral. It is the largest and the most superficial (outermost) of the three flat muscles of the lateral anterior abdomen. The obliques wrap around the trunk on each side to form our waists and join to the linea alba, a band of connective tissue running down the front of the abdomen.

Origin:

Lowest 8 ribs.

Insertion:

  1. Front 1/2 of the iliac crest.
  2. Linea alba.

The external oblique pulls the chest downwards and compresses the abdominal cavity, which increases the intra-abdominal pressure. It also has limited actions in flexion and rotation of the vertebral column.

The internal oblique muscle is the intermediate muscle of the abdomen, lying deep to the external oblique and just superficial to the transverse abdominal muscle. The internal obliques wrap around the waist and insert into the linea alba, a cord-like strip of connective tissue running down the center of the abdomen.

The internal oblique performs two major functions. First, as an accessory muscle of respiration, it acts as an antagonist to the diaphragm, helping to reduce the volume of the chest cavity during exhalation. When the diaphragm contracts, it pulls the lower wall of the chest cavity down, increasing the volume of the lungs. When the internal obliques contract they compress the organs of the abdomen, pushing them up into the diaphragm which intrudes back into the chest cavity reducing the volume of the air filled lungs, producing an exhalation.

Also, its contraction rotates and side-bends the trunk by pulling the rib cage and midline towards the hip and lower back, of the same side.

Origin:

  1. Iliac crest.
  2. Inguinal ligament.
  3. Thoracolumbar fascia.

Insertion:

  1. Lower 3-4 ribs.
  2. Linea alba.

Pain and symptoms associated with the External and Internal Oblique muscles

– Pain in the side, in the waist area
– Pain in the groin area
– Pain in the low abdomen
– Heartburn and indigestion
– Testicle pain
– Bladder pain and incontinence
– Pain in the pelvis area

Activities that cause obliques muscle pain and symptoms

– Abdominal scars from surgery
– Over exercising muscles (twisting and side bending exercises)
– Rowing
– Raking leaves
– Lifting using tools like shovels or pitchforks
– Chronic coughing
– Sitting for long periods of time
– Slouching posture

The Quadratus Lumborum, or QL, can perform different actions:

  1. Lateral flexion of the vertebral column, with ipsilateral contraction.
  2. Extension of the vertebral column, with bilateral contraction.
  3. Elevates the Ilium (bone), with ipsilateral contraction.

 

Origin:

  1. Posterior iliac crest.
  2. Iliolumbar ligament.

Insertion:

  1. Twelfth rib.
  2. Transerve processes of L1-L4.

This muscle is a common source of lower back pain. The QL connects the pelvis to the spine and is capable of extending the lower back when contracting bilaterally. When the lower fibers of the erector spinae are weak or inhibited, the QLs pick up the slack. Given their mechanical disadvantage, constant contraction while you are seated can overuse the QLs, resulting in muscle fatigue. A constantly contracted QL, like any other muscle, will experience decreased blood flow. In time, adhesions in the muscle and fascia may develop, the end point of which is the muscle spasm.

Pain and symptoms associated with the Quadratus Lumborum muscle

– Pain in the low back, constant deep aching even at rest
– Pain in the hips and buttocks
– Groin pain
– Pelvic pain
– Pain down the front of the thigh
– Low abdominal pain
– Stabbing back and or abdominal pain when coughing or sneezing

Activities that cause quadratus lumborum pain and symptoms
– Lifting heavy objects
– Twisting while lifting
– Sleeping on a mattress that is too soft
– Horseback riding
– Golfing
– Kayaking
– Leg length discrepancy – one leg shorter than other. This can be the way you were born or due to injury. It is often seen after a leg has been in a cast or splint.
– The QL muscles are often affected when you slip and or fall