Surgical neck of the humerus
Encyclopedia
The surgical neck of the humerus is a constriction below the tubercles of the greater tubercle
and lesser tubercle
.
It is much more frequently fractured than the anatomical neck of the humerus. A fracture in this area is most likely to cause damage to the axillary nerve
. Damage to the axillary nerve would effect function of the teres minor muscle and deltoid muscle , resulting in loss of abduction of arm (from 15-90 degrees), weak flexion, extension, and rotation of shoulder. Paralysis of deltoid & teres minor results in Flat shoulder deformity and loss of sensation of the skin over a small part of the lateral upper arm
Greater tubercle
The greater tubercle of the humerus is situated lateral to the head of the humerus and posteriolateral to the lesser tubercle.Its upper surface is rounded and marked by three flat impressions....
and lesser tubercle
Lesser tubercle
The lesser tubercle of the humerus, although smaller, is more prominent than the greater tubercle: it is situated in front, and is directed medially and anteriorly....
.
It is much more frequently fractured than the anatomical neck of the humerus. A fracture in this area is most likely to cause damage to the axillary nerve
Axillary nerve
The axillary nerve or the circumflex nerve is a nerve of the human body, that comes off the of the brachial plexus at the level of the axilla and carries nerve fibers from C5 and C6...
. Damage to the axillary nerve would effect function of the teres minor muscle and deltoid muscle , resulting in loss of abduction of arm (from 15-90 degrees), weak flexion, extension, and rotation of shoulder. Paralysis of deltoid & teres minor results in Flat shoulder deformity and loss of sensation of the skin over a small part of the lateral upper arm