While this slightly closes the angle between the clavicle and the scapula, it also widens the shoulder. The pronators are the pronator teres and the pronator quadratus, and the supinator is the only one that turns the forearm anteriorly. The pronators are the pronator teres and the pronator quadratus. Along with the adductor longus, adductor brevis, adductor magnus, and pectineus, the strap-like gracilis adducts the thigh in addition to flexing the leg at the knee. This deviation is called the carrying angle. This is the most frequent forearm fracture and is a common injury in persons over the age of 50, particularly in older women with osteoporosis. The expanded distal end of each metacarpal bone articulates at the metacarpophalangeal joint with the proximal phalanx bone of the thumb or one of the fingers.
The first metacarpal bone, at the base of the thumb, is separated from the other metacarpal bones. The pectineus muscle adducts and flexes the femur at the hip. If compression occurs, the resulting ischemia lack of oxygen due to reduced blood flow can quickly produce irreparable damage to the forearm muscles. However, the primary support for the acromioclavicular joint comes from a very strong ligament called the coracoclavicular ligament see. The two axial muscles are the pectoralis major and the latissimus dorsi. The pronators are the pronator teres and the pronator quadratus.
The forearm is the region of the upper limb located between the elbow and wrist joints. These consist of the arm, located between the shoulder and elbow joints; the forearm, which is between the elbow and wrist joints; and the hand, which is located distal to the wrist. The three margins or borders of the scapula, named for their positions within the body, are the superior border of the scapula, the medial border of the scapula, and the lateral border of the scapula. Your clavicle provides the only direct connection between your pectoral girdle and axial skeleton. Muscles That Position the Pectoral Girdle. Each of these articulations is a carpometacarpal joint see.
The small bony bumps located immediately above and below the glenoid cavity are the supraglenoid tubercle and the infraglenoid tubercle, respectively. The sternal end is also anchored to the first rib by the costoclavicular ligament. Muscles that Position the Pectoral Girdle Table 8 Position in the thorax Movement Target Target motion direction Prime mover Origin Insertion Anterior thorax Stabilizes clavicle during movement by depressing it Clavicle Depression Subclavius First rib Inferior surface of clavicle Anterior thorax Rotates shoulder anteriorly throwing motion ; assists with inhalation Scapula; ribs Scapula: depresses; ribs: elevates Pectoralis minor Anterior surfaces of certain ribs 2—4 or 3—5 Coracoid process of scapula Anterior thorax Moves arm from side of body to front of body; assists with inhalation Scapula; ribs Scapula: protracts; ribs: elevates Serratus anterior Muscle slips from certain ribs 1—8 or 1—9 Anterior surface of vertebral border of scapula Posterior thorax Elevates shoulders shrugging ; pulls shoulder blades together; tilts head backwards Scapula; cervical spine Scapula: rotests inferiorly, retracts, elevates, and depresses; spine: extends Trapezius Skull; vertebral column Acromion and spine of scapula; clavicle Posterior thorax Stabilizes scapula during pectoral girdle movement Scapula Retracts; rotates inferiorly Rhomboid major Thoracic vertebrae T2—T5 Medial border of scapula Posterior thorax Stabilizes scapula during pectoral girdle movement Scapula Retracts; rotates inferiorly Rhomboid minor Cervical and thoracic vertebrae C7 and T1 Medial border of scapula Muscles That Move the Humerus Similar to the muscles that position the pectoral girdle, muscles that cross the shoulder joint and move the humerus bone of the arm include both axial and scapular muscles and. The pronators are the pronator teres and the pronator quadratus, and the supinator is the only one that turns the forearm anteriorly. The shaft portions of both the ulna and radius have an interosseous border, whereas the distal ends of each bone have a pointed styloid process. The four distal carpal bones are also held together as a group by ligaments. The two axial muscles are the pectoralis major and the latissimus dorsi.
The rest of the compartments produce extension. The inferior margin of the trochlear notch is formed by a prominent lip of bone called the coronoid process of the ulna. The distal humerus is flattened, forming a lateral supracondylar ridge that terminates at the small lateral epicondyle. This involves a complete transverse fracture across the distal radius that drives the separated distal fragment of the radius posteriorly and superiorly. Together, the clavicle, acromion, and spine of the scapula form a V-shaped bony line that provides for the attachment of neck and back muscles that act on the shoulder, as well as muscles that pass across the shoulder joint to act on the arm.
The large and powerful muscles of the hip that move the femur generally originate on the pelvic girdle and insert into the femur. Your friend runs out of gas and you have to help push his car. The metacarpal bones are numbered 1—5, beginning at the thumb. The medial end, known as the sternal end of the clavicle, has a triangular shape and articulates with the manubrium portion of the sternum. The lateral rotators of the femur at the hip are the piriformis, obturator internus, obturator externus, superior gemellus, inferior gemellus, and quadratus femoris.
Together, the radiocarpal and midcarpal joints are responsible for all movements of the hand at the wrist. The elbow joint is formed by the articulation between the trochlea of the humerus and the trochlear notch of the ulna, plus the articulation between the capitulum of the humerus and the head of the radius. The neck of the radius is the narrowed region immediately below the expanded head. The scapula is located on the posterior side of the shoulder. This process projects anteriorly and curves laterally. In more derived tetrapods the dermal part of the girdle was gradually reduced and the scapulocoracoid split into a dorsal scapula and a ventral coracoid. The small, rounded area that forms the distal end is the head of the ulna.
It also commonly occurs following a high-speed fall onto the hand during activities such as snowboarding or skating. The right and left pectoral girdles are not joined to each other, allowing each to operate independently. The deep anterior compartment produces flexion and bends fingers to make a fist. The extensors are the triceps brachii and anconeus. An interphalangeal joint is one of the articulations between adjacent phalanges of the digits see.
The deep anterior compartment produces flexion as well. The isolated scapula is shown here from its anterior deep side and its posterior superficial side. Extending laterally from the spine is a flattened and expanded region called the acromion or acromial process. Because the sternoclavicular joint is strong and rarely dislocated, excessive force results in the breaking of the clavicle, usually between the middle and lateral portions of the bone. These muscles allow your fingers to also make precise movements for actions, such as typing or writing. The hypothenar muscles are on the medial aspect of the palm, and the intermediate muscles are midpalmar. The muscles originating in the forearm move the wrists, hands, and fingers.
The forearm is the origin of the extrinsic muscles of the hand. The axial skeleton forms the central axis of the body and consists of the skull, vertebral column, and thoracic cage. This is the large, round, smooth region that faces medially. This muscle allows us to sit cross-legged. At the shoulder, the coracoid process is located inferior to the lateral end of the clavicle.