Page 63 - Adams and Stashak's Lameness in Horses, 7th Edition

Functional Anatomy of the Equine Musculoskeletal System 29

Semispinalis capitis m.
Supraspinous bursa
VetBooks.ir Dorsoscapular ligament

Splenius m.

Serratus dorsalis cranialis m.
Serratus ventralis
cervicis m.

Subclavius m.

Superficial cervical
lymphocenter

Cleidobrachialis m.

Pectoralis ascendens m.

Serratus ventralis thoracis m.
Figure 1.29. Right shoulder and dorsoscapular ligament. Spines of thoracic vertebrae 2–5 are outlined by dashed lines.

Within the shoulder joint the articular surface of the approximately 145° in extension and decrease to 80° in
humeral head has approximately twice the area of flexion. 16
the glenoid cavity of the scapula even with the small
extension afforded by the glenoid lip around the rim.
The great stability of this joint is largely owed to the MuScleS of tHe Scapula
support of the surrounding muscles. In spite of its clas­ In the scapular region the flat, triangular trapezius
sification as a ball‐and‐socket joint, major movements muscle covers parts of eight underlying muscles. The cer­
are limited to flexion and extension; muscles around the vical part of the trapezius arises by a thin aponeurosis
joint restrict abduction and adduction, and rotation is from most of the funicular part of the nuchal ligament
very limited. While standing, the caudal angle of the and inserts on the scapular spine and fascia of the shoul­
shoulder joint is 120°–130°. The angle can increase to der and arm. The thoracic part of the trapezius takes an