Human Anatomy Vol 1

UPPER LIMB

Suprascapular nerve,

vein and artery

Supraspinatus

lnfraspinatus

Teres minor

Pseudoganglion on the

nerve to teres minor from

posterior division which

continues as upper lateral

cutaneous branch

Anterior division for deep

aspect of deltoid

Medial border of humerus

Deltoid

Radial nerve and profunda

brachii vessels in lower

triangular space

Teres major

Quadrangular space with two divisions

of axillary nerve and posterior

circumflex humeral artery and vein

Long head of triceps brachii

Fig. 6.12: The intermuscular spaces in the scapular region, including the quadrangular, upper triangular and lower triangular spaces

Suprascapular nerve and vessels are also shown

Rhomboid major

Circumflex sca

artery with vein in

upper triangular space

Axillary or circumflex nerve is an important nerve

because it supplies the deltoid muscle which is the main

abductor of the arm. Surgically it is important, because

it is commonly involved in dislocations of the shoulder

and in fractures of the surgical neck of the humerus.

The axillary nerve is a smaller terminal branch of

the posterior cord of the brachial plexus (C5, C6).

Root aalue: Its root value is ventral rami of cervical 5,

6 segments of spinal cord (see Fig. a.7\.

Course

Axillary nerve courses through lower part of axilla into

the quadrangular space where it terminates by dividing

into two branches (Fig. 6.6).

Relotions ond Blonches

a. In the lower part of the axilla, the nerve runs

downwards behind the third part of the axillary

artery. Here it lies on the subscapularis muscle. It is

related medially to the median nerve, and laterally

to the coracobrachialis.

The nerve leaves the axilla by winding round the

lower border of the subscapularis in close relation

to the lowest part of the capsule of the shoulder joint

where it gives a branch to the capsule of the joint

and enters the quadrangular space (Fig. 6.8).

b. The nerve then passes backwards through the

quadrangular space. Here it is accompanied by the

posterior circumflex humeral vessels and has the

following relations (Fig. 6.72).

. Superiorly:
i. Subscapularis or teres minor.
ii. Lowest part of the capsule of the shoulder
joint.
o Laterally: Surgical neck of humerus.
. lnferiorly; Teres major.
. Medially: Long head of the triceps brachii.
In the quadrangular space, the nerve divides into
anterior and posterior branches in relation to the
deltoid muscle (Fig. 6.6)

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