Scapular Region

Gross Anatomy


Scapular Region


Anatomy Tables for Today's Topic

Bones of the Shoulder Region
Muscles of the Shoulder Region
Nerves of the Shoulder Region
Arteries of the Shoulder Region
Joints of the Shoulder Region
Topographic Anatomy of the Shoulder Region

Bones of the Scapular Region

Bone Structure Description Notes
scapula   the bone of the shoulder the scapula floats in a sea of muscles, so it is difficult to fracture; it articulates with only one bone - the clavicle at the coracoclavicular and acromioclavicular joints
superior border the superior edge of the scapula the superior border of the scapula is marked by the scapular notch laterally
medial border the border of the scapula that runs from the superior angle to the inferior angle it is an important site of muscle attachments for the intermediate layer of back muscles
superior angle the angle of the scapula formed at the union of the superior and medial borders it is the attachment site for the levator scapulae m.
lateral border the portion of the scapula that runs inferomedially from the infraglenoid tubercle to the inferior angle it is an important site of attachment for the teres major m. and teres minor m.; it has a groove for passage of the circumflex scapular a.
inferior angle the angle of the scapula formed by the union of the medial and lateral borders the inferior angle of the scapula often has a slip of origin of the latissimus dorsi attached to it
glenoid fossa the articular surface located at the junction of the superior and lateral borders of the scapula it articulates with the head of the humerus; it is deepened by a fibrocartilaginous rim called the glenoid labrum
supraglenoid tubercle a projection of bone located superior to the glenoid cavity it is the attachment site for the tendon of the long head of the biceps brachii m.
infraglenoid tubercle a projection of bone located inferior to the glenoid cavity it is the attachment site of the tendon o of the long head of the triceps brachii m.
spine a heavy ridge that runs from the medial border of the scapula to the acromion process it supports the acromion process; it divides the posterior surface of the scapula into a supraspinatous fossa and an infraspinatous fossa
scapular notch a notch on the superior border of the scapula located medial to the attachment of the coracoid process it is bridged by the superior transverse scapular ligament; the suprascapular a. passes superior to the superior transverse scapular ligament and the suprascapular n. passes inferior to it (Army goes over the bridge, Navy goes under the bridge)
coracoid process a beak-like process that projects anteriorly from the lateral end of the superior border of the scapula it is the attachment site for the short head of the biceps brachii m., the coracobrachialis m., the pectoralis minor m. and the coracoacromial and coracoclavicular ligaments
acromion a broad, flat process located at the lateral end of the scapular spine it articulates with the clavicle through a synovial joint (acromioclavicular joint)
supraspinatous fossa a broad depression located superior to the spine of the scapula it is the site of origin of the supraspinatus m.
infraspinatous fossa a broad depression located inferior to the spine of the scapula it is the site of origin of the infraspinatus m.
humerus   the bone of the arm (brachium) the humerus articulates proximally with the scapula at the glenoid fossa; it articulates distally with the radius and ulna at the elbow joint
head the smooth, rounded proximal end of the ulna it articulates with the glenoid cavity of the scapula to form the shoulder joint
anatomical neck the constricted region located inferolateral to the head it is located at the circumference of the smooth articular surface of the head
surgical neck the proximal part of the shaft of the humerus it is located inferior to the greater and lesser tubercles; it is a site of frequent fracture; fractures of the surgical neck of the humerus endanger the axillary n. and the posterior circumflex humeral a.
greater tubercle the large projection located lateral to the head of the humerus it is the attachment site of the supraspinatus, infraspinatus & teres minor mm.
lesser tubercle the projection located lateral to the head of the humerus on the anterior surface it is the insertion site of the subscapularis m.
intertubercular groove the groove on the anterior surface of the humerus that is located between the crest of the greater tubercle and the crest of the lesser tubercle it is occupied by the tendon of the long head of the biceps brachii m.; the transverse humeral ligament spans the intertubercular groove and holds the biceps tendon in place; it is the attachment site for the tendon of the pectoralis major (lateral lip), teres major (medial lip), and latissimus dorsi (floor)
crest of the greater tubercle the ridge of bone on the anterior surface of the humerus extending inferiorly from the greater tubercle it forms the lateral lip of the intertubercular groove; it is the attachment site for the transverse humeral ligament and the pectoralis major m.
crest of the lesser tubercle the ridge of bone on the anterior surface of the humerus extending inferiorly from the lesser tubercle it forms the medial lip of the intertubercular groove; it is the attachment site for the transverse humeral ligament and the teres major m.
deltoid tuberosity the roughened process on the lateral surface of the mid-shaft of the humerus it is the insertion site of the deltoid m.

Muscles of the Scapular Region

Muscle Origin Insertion Action Innervation Artery Notes
deltoid lateral one-third of the clavicle, acromion, the lower lip of the crest of the spine of the scapula deltoid tuberosity of the humerus abducts arm; anterior fibers flex & medially rotate the arm; posterior fibers extend & laterally rotate the arm axillary nerve (C5,6) from the posterior cord of the brachial plexus posterior circumflex humeral a. the deltoid muscle is the principle abductor of the arm but due to poor mechanical advantage it cannot initiate this action; it is assisted by the supraspinatus m.
teres major dorsal surface of the inferior angle of the scapula crest of the lesser tubercle of the humerus adducts the arm, medially rotates the arm, assists in arm extension lower subscapular nerve (C5,6) from the posterior cord of the brachial plexus circumflex scapular a. teres major inserts beside the tendon of latissimus dorsi, and assists latissimus in its actions
triceps brachii long head: infraglenoid tubercle of the scapula; lateral head: posterolateral humerus & lateral intermuscular septum; medial head: posteromedial surface of the inferior 1/2 of the humerus olecranon process of the ulna extends the forearm; the long head extends and adducts arm radial nerve deep brachial (profunda brachii) a. long head of the triceps separates the triangular and quadrangular spaces (teres major, teres minor and the humerus are the other boundaries); all three heads of origin insert by a common tendon
rotator cuff
supraspinatus supraspinatous fossa greater tubercle of the humerus (highest facet) abducts the arm (initiates abduction) suprascapular nerve (C5,6) from the superior trunk of the brachial plexus suprascapular a. supraspinatus initiates abduction of the arm, then the deltoid muscle completes the action; a member of the rotator cuff group
infraspinatus infraspinatous fossa greater tubercle of the humerus (middle facet) laterally rotates the arm suprascapular nerve suprascapular a. infraspinatus, supraspinatus, teres minor and subscapularis are the rotator cuff muscles
teres minor upper 2/3 of the lateral border of the scapula greater tubercle of the humerus (lowest facet) laterally rotates the arm axillary nerve (C5,6) from the posterior cord of the brachial plexus circumflex scapular a. fixes the head of the humerus in the glenoid fossa during abduction & flexion of the arm; a member of the rotator cuff group
subscapularis medial two-thirds of the costal surface of the scapula (subscapular fossa) lesser tubercle of the humerus medially rotates the arm; assists extention of the arm upper and lower subscapular nerves (C5,6) subscapular a. subscapularis, supraspinatus, infraspinatus, and teres minor are the rotator cuff muscles

Nerves of the Scapular Region

Nerve Source Branches Motor Sensory Notes
axillary n. posterior cord of the brachial plexus superior lateral brachial cutaneous nerve deltoid, teres minor skin of the upper lateral arm axillary n. is endangered by surgical neck fractures
lower subscapular n. posterior cord of the brachial plexus (C5, C6) unnamed muscular brs. subscapularis m., teres major m. no cutaneous branches subscapularis and teres major are synergists (medial rotation of the humerus)
middle subscapular n. posterior cord of the brachial plexus (C7, C8) unnamed muscular brs. latissimus dorsi m. no cutaneous branches also called the thoracodorsal n.
suprascapular n. superior trunk of the brachial plexus (C5-C6) no named branches supraspinatus m., infraspinatus m. no cutaneous branches suprascapular n. passes through the scapular notch inferior to the superior transverse scapular ligament
thoracodorsal n. posterior cord of the brachial plexus (C7, C8) unnamed muscular brs. latissimus dorsi m. no cutaneous branches also called the middle subscapular n.
upper subscapular n. posterior cord of the brachial plexus (C5, C6) unnamed muscular brs. subscapularis m. no cutaneous branches subscapularis is a strong medial rotator of the humerus

Arteries of the Scapular Region

Artery Source Branches Supply to Notes
anterior circumflex humeral axillary a., 3rd part unnamed muscular branches deltoid m.; arm muscles near the surgical neck of the humerus anterior circumflex humeral a. anastomoses with the posterior circumflex humeral a.
posterior circumflex humeral axillary a., 3rd part unnamed muscular branches deltoid; arm muscles near the surgical neck of the humerus posterior circumflex humeral a. anastomoses with the anterior circumflex humeral a.; it passes through the quadrangular space with the axillary nerve
axillary subclavian a. (axillary a. is the continuation of the subclavian lateral to the 1st rib) 1st part: superior thoracic a.; 2nd part: thoracoacromial a., lateral thoracic a.; 3rd part: anterior humeral circumflex a., posterior humeral circumflex a., subscapular a. pectoral region, shoulder region and upper limb pectoralis minor m. crosses anterior to the axillary artery and is used to delineate the 3 parts mentioned at left
circumflex scapular subscapular a. unnamed muscular branches teres major m., teres minor m., infraspinatus m. circumflex scapular a. anastomoses with the suprascapular a. and the dorsal scapular a. to form the scapular anastomosis
dorsal scapular subclavian a., 3rd part unnamed muscular branches levator scapulae m., rhomboideus major m., rhomboideus minor m. dorsal scapular a. anastomoses with the suprascapular a. and the subscapular a. to form the scapular anastomosis; dorsal scapular a is a branch of the transverse cervical a. in ~30% of cases
subscapular axillary a., 3rd part circumflex scapular a., thoracodorsal a. subscapularis m., teres major m., teres minor m., infraspinatus m. the circumflex scapular branch of the subscapular a.anastomoses with the suprascapular a. and the dorsal scapular a. in the scapular anastomosis
suprascapular thyrocervical trunk muscular supraspinatus & infraspinatus, shoulder joint anastomoses with the circumflex scapular a. and the dorsal scapular a. to form the scapular anastomosis
thoracodorsal subscapular a. unnamed muscular branches latissimus dorsi m. thoracodorsal a. accompanies the thoracodorsal n.

Joints of the Scapular Region

Joint or ligament Description Notes
acromioclavicular joint the joint between the distal end of the clavicle and the acromion of the scapula a plane synovial joint; the shape of the articulation encourages the acromion to slide inferior to the clavicle during dislocation (shoulder separation) a condition that occurs when the coracoclavicular ligament is torn; a small articular disk occurs within this joint capsule
coracoacromial ligament the ligament that connects the coracoid process to the acromion of the scapula it passes superior to both the head of the humerus and the supraspinatus tendon; it provides support for the head of the humerus that prevents superior dislocation
coracoclavicular joint the joint between the coracoid process of the scapula and the inferior surface of the lateral portion of the clavicle a syndesmosis; this joint provides stability to the acromioclavicular joint
coracoclavicular ligament the ligament that connects the upper surface of the coracoid process to the under surface of the clavicle it has two parts: conoid ligament (posteromedial part) and trapezoid ligament; tearing of the coracoclavicular ligament permits the acromion to move inferior to the distal end of the clavicle (shoulder separation), a condition which could result from a fall on the point of the shoulder
glenohumeral ligament, inferior a ligament reinforcing the anterior wall of the capsule of the glenohumeral joint it connects the humerus to the scapula; a thickening of the anteroinferior shoulder joint capsule
glenohumeral ligament, middle a ligament reinforcing the anterior wall of the capsule of the glenohumeral joint it connects the humerus to the scapula; a thickening of the anterior shoulder joint capsule
glenohumeral ligament, superior a ligament reinforcing the anterior wall of the capsule of the glenohumeral joint it connects the humerus to the scapula; a thickening of the anterosuperior shoulder joint capsule
shoulder joint the articulation between the head of the humerus and the glenoid fossa of the scapula a synovial ball and socket joint; the glenoid labrum deepens the socket; glenohumeral ligaments reinforce the joint capsule anteriorly; the tendon of the long head of the biceps brachii m. passes through the shoulder joint cavity; the shoulder joint is supported by the muscles of the rotator cuff group (supraspinatus, infraspinatus, teres minor and subscapularis); also known as the glenohumeral joint; it is frequently dislocated
sternoclavicular joint the joint what connects the clavicle with the sternum a synovial joint; its joint capsule is subdivided by a fibrous articular disk; it is strengthened by the sternoclavicular, interclavicular and costoclavicular ligaments; the sternoclavicular joint has the range of movement, but not the form, of a ball and socket joint
sternoclavicular ligament a ligament that reinforces the capsule of the sternoclavicular joint the sternoclavicular ligament has two parts: anterior and posterior; it is a very strong ligament; the combined effect of this ligament, the costoclavicular ligament and the interclavicular ligament is to produce a very strong sternoclavicular joint that seldom dislocates
transverse scapular ligament, superior a ligament that spans the suprascapular notch of the scapula it converts the suprascapular notch into a foramen; the suprascapular a. passes superior to the ligament and the suprascapular n. passes inferior to the ligament (Army over the bridge, Navy under the bridge)

Topographic Anatomy of the Scapular Region

Structure/Space Description/Boundaries Significance
quadrangular space the space bounded by the teres minor m. superiorly, the teres major m. inferiorly, the long head of the triceps brachii m. medially and the humerus laterally the axillary n. and the posterior circumflex humeral a. pass through this space
triangular interval the interval between the teres major m. superiorly, long head of the triceps brachii m. medially and humerus laterally the radial n. passes through this interval to get from the axilla to the posterior surface of the humerus
triangular space the space bounded by the teres minor m. superiorly, the teres major m. inferiorly and the long head of the triceps brachii m. laterally the circumflex scapular vessels are located in this space as they pass from the axilla to the dorsum of the scapula


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Upper Limb

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Some of the material presented in these tables is contained in the book:
MedCharts Anatomy by Thomas R. Gest and Jaye Schlesinger
Published by ILOC, Inc., New York. Copyright 1995.

Content of tables edited for use in this course by Patrick W. Tank, Ph.D.
Copyright 2005, Department of Neurobiology and Developmental Sciences, University of Arkansas for Medical Sciences.

Unauthorized use is prohibited.