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You are watching: Scapular region to which the clavicle connects
The scapula is a flat, triangular-shaped bone (colloquially as the "shoulder blade"). It is situated in the top thoracic region ~ above the dorsal surface ar of the rib cage. That connects with the humerus in ~ the glenohumeral joint and also the clavicle at the acromioclavicular joint to type the shoulder joint. In total, 17 different muscles connect to the scapula, which renders it complicated to fracture.
Structure and also Function
The scapula is a website of attachments for many muscles and has numerous processes, projections, and also surfaces for attachment. The scapula has actually three angle (superior/medial, lateral, inferior), three boundaries (medial, lateral/axillary, and superior), and two surface (ventral and dorsal). The scapula has 3 processes: the acromion, the spine, and also the coracoid process. Muscle attachments to this landmarks are covered in the "Muscles" section.
The ventral surface that the scapula abuts the thoracic rib cage and has a large concavity called the subscapular fossa wherein the subscapularis attaches. Three ridges in ~ this fossa enable for tendinous attachment. The dorsal surface ar divides into two unequal parts via the scapular spine i m sorry runs across from the posterior scapula prior to forming the acromion. Over the spine is the supraspinous fossa and below that is the infraspinous fossa. A ridge runs under the infraspinous fossa near the lateral border native the glenoid cavity to just above the worse angle. This ridge separates the teres major and minor muscle from the infraspinatus muscle. The spinoglenoid notch connects the 2 fossae, i beg your pardon is located under the acromion and is whereby the suprascapular nerve and also artery run on the way to offering the infraspinatus muscle. The acromion is one oblong continuation of the spine that operation laterally then anteriorly over the supraspinous fossa and also is the summit the the shoulder on palpation. The premium border the the scapula extends native the exceptional angle to the coracoid process. The coracoid process is a hook-like framework that comes turn off anteriorly from the lateral superior element of the ventral side of the scapula. Favor the acromion, the is an attachment suggest for muscles and ligaments.
At the base of the coracoid, over there is a notch that is closed turn off by the exceptional transverse scapular ligament superiorly, developing a foramen. The suprascapular nerve runs v this foramen while the suprascapular artery runs just above the ligament. The lateral edge of the scapula is the location of the glenoid cavity; this is where the humeral head articulates through the scapula. At the spare part of this cavity, a fibrocartilagenous structure called the glenoid labrum acts come deepen the cavity as to accommodate more of the humeral head. Just listed below the cavity is one impression referred to as the infraglenoid tuberosity where the lengthy head that the triceps brachii originates. The ligaments of the scapula are mainly named based on the two points lock attach. They are the transverse scapular ligament (discussed earlier), coracoacromial ligament, coracoclavicular ligament, coracohumeral ligament, glenohumeral ligaments, and also acromioclavicular ligament.
The muscles that attach to the scapula enable it to execute six movements:
Retraction (adduction): The rhomboids and also middle trapezius separate the scapula indigenous the thoracic wall, energetic when performing rowing motions
Protraction (abduction): The serratus anterior brings the scapula versus the thoracic wall, active when reaching forward
As with various other bones, the scapula is acquired from the embryologic mesoderm. That osteogenic advance beings in week 11 of human embryogenesis. <1>
Blood Supply and Lymphatics
The blood supply of the posterior surface of the scapula is composed of one anastomosis of several arteries derived from the thyrocervical trunk (a branch the the subclavian artery) and also axilla artery (continuation that the subclavian artery past the lateral margin that the first rib):
Transverse cervical artery - runs follow me the medial border of the scapula. May administer a deep (or descending) branch the is also known together the dorsal scapular artery. However, this artery more frequently branches off the subclavian artery.
Subscapular artery - offers blood supply for subscapularis muscle as much as the inferior angle of the scapula
Circumflex scapular artery - branch that the subscapular artery. Forms an anastomosis through the suprascapular artery and the deep branch that the transverse cervical artery.
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Venous drainage of the scapula: Primarily via the axillary vein and suprascapular veins
The lymph nodes linked with the scapula include the axillary and the supraclavicular lymph nodes.
The intrinsic muscles of the scapula affix directly to the surface of the bone. These muscles space the 4 members the the rotator cuff and act come stabilize the glenohumeral joint. This include: