scapula bone -Anatomy
hello,
INTRODUCTION-
It is a thin and flat bone on the posterolateral aspect to the thoracic cage.is the bone that connects the humerus (upper arm bone) with the clavicle (collar bone). Like their connected bones the scapulae are paired, with the scapula on the left side of the body being roughly a mirror image of the right scapula. In early Roman times, people thought the bone resembled a trowel, a small shovel.
General features-
SURFACES:-
1. The costal surface or subscapular fossa is concave and is directed medially. It is marked by 3 longitudinal ridges. At the upper part of the fossa is a transverse depression, where the bone appears to be bent on itself along a line at right angles to and passing through the center of the glenoid cavity, forming a considerable angle, called the subscapular angle; this gives greater strength to the body of the bone by its arched form, while the summit of the arch serves to support the spine and acromion.
The costal surface superior of the scapula is the origin of 1st digitation for the serratus anterior origin.
2.The dorsal surface gives attachments to the spine of the scapula which divides the surface into a smaller supraspinous fossa and a large infraspinous fossa. There is a ridge on the outer part of the back of the scapula. This runs from the lower part of the glenoid cavity, downward and backward to the vertebral border, about 2.5 cm above the inferior angle. Attached to the ridge is a fibrous septum, which separates the infraspinatus muscle from the Teres major and Teres minor muscles. The upper two-thirds of the surface between the ridge and the axillary border is narrow, and is crossed near its center by a groove for the scapular circumflex vessels; the Teres minor attaches here.
The broad and narrow portions above alluded to are separated by an oblique line, which runs from the axillary border, downward and backward, to meet the elevated ridge: to it is attached a fibrous septum which separates the Teres muscles from each other.
Its lower third presents a broader, somewhat triangular surface, the Inferior angle of the scapula, which gives origin to the Teres major, and over which the Latissimus dorsi glides; frequently the latter muscle takes origin by a few fibers from this part.
BORDERS:-
The superior border is thin and shorter. Near the rootof the coracoid process it presents the suprascapular notch. This notch is converted into a foramen by the superior transverse scapular ligament, and serves for the passage of the suprascapular nerve; sometimes the ligament is ossified.
The adjacent part of the superior border affords attachment to the omohyoideus.
The latereal border is thick. At the upper end it presents the infraglenoid tubercle. It begins above at the lower margin of the glenoid cavity, and inclines obliquely downward and backward to the inferior angle.Immediately below the glenoid cavity is a rough impression, the infraglenoid tuberosity, about 2.5 cm (1 in). in length, which gives origin to the long head of the triceps brachii; in front of this is a longitudinal groove, which extends as far as the lower third of this border, and affords origin to part of the subscapularis.
The inferior third is thin and sharp, and serves for the attachment of a few fibers of the teres major behind, and of the subscapularis in front.
The medial border is thin. It extend from the superior angle to the inferior angle.Four muscles attach to the medial border. Serratus anterior has a long attachment on the anterior lip. Three muscles insert along the posterior lip, the levator scapulae (uppermost), rhomboid minor (middle), and to the rhomboid major (lower middle).
MOVEMENTS:-
Movements of the scapula are brought about by the scapular muscles. The scapula can perform six actions:
Elevation: upper trapezius and levator scapula
Depression: lower trapezius
Retraction (adduction): rhomboids and middle trapezius
Protraction (abduction): serratus anterior
Upward rotation: upper and middle trapezius
Downward rotation: rhomboids
PROCESSES:-
1. The spine or spinous process is a triangular plate of the bone with 3 border and 2 surfaces. It divides the dorsal surface of the scapula into supraspinous and infraspinous fossa. Its posterior border is called as crest of spine it has 2 lips , upper and lower lip.
2. The acromion has 2 border , medial and lateral ; 2 surfaces , superior and inferior and a facet foe the calvicle.
3. The coracoid process is directed forward and slightly lateral.
SIDE DETERMINATION-
1. The lateral or glenoid angle is large and bear the glenoid cavity.
2. The dorsal suraface is convex and is divided by the triangular spine into the supraspinous and infraspinous fossa.
3. The thickest lateral border runs from the glenoid cavity above to the inferior angle below.
OSTEOLOGY-
MYOLOGY-
LIGAMENTS-
1.glenoid labrum
2. coracoacromial ligament.
3. coracohumeral ligament.
4. coracocalvicular ligament.
CLINICAL ANATOMY-
Paralysis of the serratus anterior causes 'winging' of scapula . The medial border of the bone becomes unduly prominent ,and the arm can not be abducted beyond 90 degrees.
INTRODUCTION-
It is a thin and flat bone on the posterolateral aspect to the thoracic cage.is the bone that connects the humerus (upper arm bone) with the clavicle (collar bone). Like their connected bones the scapulae are paired, with the scapula on the left side of the body being roughly a mirror image of the right scapula. In early Roman times, people thought the bone resembled a trowel, a small shovel.
General features-
SURFACES:-
1. The costal surface or subscapular fossa is concave and is directed medially. It is marked by 3 longitudinal ridges. At the upper part of the fossa is a transverse depression, where the bone appears to be bent on itself along a line at right angles to and passing through the center of the glenoid cavity, forming a considerable angle, called the subscapular angle; this gives greater strength to the body of the bone by its arched form, while the summit of the arch serves to support the spine and acromion.
The costal surface superior of the scapula is the origin of 1st digitation for the serratus anterior origin.
2.The dorsal surface gives attachments to the spine of the scapula which divides the surface into a smaller supraspinous fossa and a large infraspinous fossa. There is a ridge on the outer part of the back of the scapula. This runs from the lower part of the glenoid cavity, downward and backward to the vertebral border, about 2.5 cm above the inferior angle. Attached to the ridge is a fibrous septum, which separates the infraspinatus muscle from the Teres major and Teres minor muscles. The upper two-thirds of the surface between the ridge and the axillary border is narrow, and is crossed near its center by a groove for the scapular circumflex vessels; the Teres minor attaches here.
The broad and narrow portions above alluded to are separated by an oblique line, which runs from the axillary border, downward and backward, to meet the elevated ridge: to it is attached a fibrous septum which separates the Teres muscles from each other.
Its lower third presents a broader, somewhat triangular surface, the Inferior angle of the scapula, which gives origin to the Teres major, and over which the Latissimus dorsi glides; frequently the latter muscle takes origin by a few fibers from this part.
BORDERS:-
The superior border is thin and shorter. Near the rootof the coracoid process it presents the suprascapular notch. This notch is converted into a foramen by the superior transverse scapular ligament, and serves for the passage of the suprascapular nerve; sometimes the ligament is ossified.
The adjacent part of the superior border affords attachment to the omohyoideus.
The latereal border is thick. At the upper end it presents the infraglenoid tubercle. It begins above at the lower margin of the glenoid cavity, and inclines obliquely downward and backward to the inferior angle.Immediately below the glenoid cavity is a rough impression, the infraglenoid tuberosity, about 2.5 cm (1 in). in length, which gives origin to the long head of the triceps brachii; in front of this is a longitudinal groove, which extends as far as the lower third of this border, and affords origin to part of the subscapularis.
The inferior third is thin and sharp, and serves for the attachment of a few fibers of the teres major behind, and of the subscapularis in front.
The medial border is thin. It extend from the superior angle to the inferior angle.Four muscles attach to the medial border. Serratus anterior has a long attachment on the anterior lip. Three muscles insert along the posterior lip, the levator scapulae (uppermost), rhomboid minor (middle), and to the rhomboid major (lower middle).
lateral border
medial border
MOVEMENTS:-
Movements of the scapula are brought about by the scapular muscles. The scapula can perform six actions:
Elevation: upper trapezius and levator scapula
Depression: lower trapezius
Retraction (adduction): rhomboids and middle trapezius
Protraction (abduction): serratus anterior
Upward rotation: upper and middle trapezius
Downward rotation: rhomboids
PROCESSES:-
1. The spine or spinous process is a triangular plate of the bone with 3 border and 2 surfaces. It divides the dorsal surface of the scapula into supraspinous and infraspinous fossa. Its posterior border is called as crest of spine it has 2 lips , upper and lower lip.
2. The acromion has 2 border , medial and lateral ; 2 surfaces , superior and inferior and a facet foe the calvicle.
3. The coracoid process is directed forward and slightly lateral.
SIDE DETERMINATION-
1. The lateral or glenoid angle is large and bear the glenoid cavity.
2. The dorsal suraface is convex and is divided by the triangular spine into the supraspinous and infraspinous fossa.
3. The thickest lateral border runs from the glenoid cavity above to the inferior angle below.
OSTEOLOGY-
MYOLOGY-
LIGAMENTS-
1.glenoid labrum
2. coracoacromial ligament.
3. coracohumeral ligament.
4. coracocalvicular ligament.
CLINICAL ANATOMY-
Paralysis of the serratus anterior causes 'winging' of scapula . The medial border of the bone becomes unduly prominent ,and the arm can not be abducted beyond 90 degrees.
Comments
Post a Comment