THE BACK THE MUSCLES THE MUSCLES OF THE BACK THE MUSCLES OF THE - PowerPoint PPT Presentation

THE BACK THE MUSCLES

THE MUSCLES OF THE BACK

THE MUSCLES OF THE BACK Muscles of the back are organized into superficial , intermediate , and deep groups . extrinsic muscles and intrinsic muscles Muscles in the superficial and intermediate groups are extrinsic muscles because they originate embryologically from locaFons other than the back.

THE MUSCLES OF THE BACK The superficial and intermediate groups are innervated by anterior rami of spinal nerves . The superficial group consists of muscles related to and involved in movements of the upper limb . The intermediate group consists of muscles aHached to the ribs and may serve a respiratory funcFon. Muscles of the deep group are intrinsic muscles because they develop in the back.

THE MUSCLES OF THE BACK The deep group are are innervated by posterior rami of spinal nerves and are directly related to movements of the vertebral column and head .

THE BACK MUSCLES • SUPERFICIAL EXTRINSIC BACK MUSCLES • INTERMEDIATE EXTRINSIC BACK MUSCLES • DEEP INTRINSIC BACK MUSCLES

SUPERFICIAL GROUP OF BACK MUSCLES THE MUSCLES OF THE BACK The muscles in the SUPERFICIAL GROUP are immediately deep to the skin and superficial fascia. They aHach the superior part of the appendicular skeleton : • clavicle • scapula • humerus to the axial skeleton : • skull • ribs • vertebral column.

SUPERFICIAL GROUP OF BACK MUSCLES THE MUSCLES OF THE BACK Because these muscles are primarily involved with movements of this part of the appendicular skeleton, they are someFmes referred to as the appendicular group . Muscles in the superficial group include the: • trapezius • laMssimus dorsi • rhomboid major • rhomboid minor • levator scapulae The rhomboid major, rhomboid minor, and levator scapulae muscles are located deep to the trapezius muscle in the superior part of the back.

SUPERFICIAL GROUP OF BACK MUSCLES THE MUSCLES OF THE BACK THE TRAPEZIUS

THE TRAPEZIUS MUSCLE THE MUSCLES OF THE BACK Each trapezius muscle is flat and triangular, with the base of the triangle situated along the vertebral column (the muscle's origin) and the apex poinFng toward the Fp of the shoulder (the muscle's inserFon) The muscles on both sides together form a trapezoid . The superior fibers of the trapezius, from the skull and upper porFon of the vertebral column, descend to aHach to the lateral third of the clavicle and to the acromion of the scapula . ContracFon of these fibers elevates the scapula .

THE TRAPEZIUS MUSCLE THE MUSCLES OF THE BACK The superior and inferior fibers work together to rotate the lateral aspect of the scapula upward - when raising the upper limb above the head. ORIGIN: Superior nuchal line, external occipital protuberance, ligamentum nuchae, spinous processes of CVII to TXII INSERTION: Lateral one third of clavicle, acromion, spine of scapula. FUNCTION: Assists in rotaFng the INNERVATION: scapula during abducFon Motor: of humerus above accessory nerve [XI]; horizontal; upper fibers elevate, middle fibers propriocepFon: adduct, and lower fibers C3 and C4 depress scapula.

SUPERFICIAL GROUP OF BACK MUSCLES THE MUSCLES OF THE BACK THE LATISSIMUS DORSI

THE LATISSIMUS DORSI THE MUSCLES OF THE BACK A large, flat triangular muscle that begins in the lower porMon of the back and tapers as it ascends to a narrow tendon that aHaches to the humerus anteriorly The movements associated with this muscle include: • extension • adducFon • medial rotaFon of the upper limb. The laFssimus dorsi can also depress the shoulder , prevenFng its upward movement. The thoracodorsal nerve of the brachial plexus (from posterior cord) innervates the laFssimus dorsi muscle.

THE LATISSIMUS DORSI THE MUSCLES OF THE BACK ORIGIN: Spinous processes of TVII to LV and sacrum, iliac crest, ribs X to XII INSERTION: Floor of intertubercular sulcus of humerus INNERVATION: Thoracodorsal nerve (C6 to C8). FUNCTION: Extends, adducts, and medially rotates humerus.

SUPERFICIAL GROUP OF BACK MUSCLES THE MUSCLES OF THE BACK THE LEVATOR SCAPULAE

THE LEVATOR SCAPULAE THE MUSCLES OF THE BACK A slender muscle that descends from the transverse processes of the upper cervical vertebrae to the upper porFon of the scapula on its medial border at the superior angle It elevates the scapula and may assist other muscles in rotaFng the lateral aspect of the scapula inferiorly. The levator scapulae is innervated by branches from the anterior rami of spinal nerves C3 and C4 and the dorsal scapular nerve ORIGIN: Transverse processes of CI to CIV INSERTION: FUNCTION: Upper porFon of medial border of scapula Elevates scapula INNERVATION: C3 to C4 and dorsal scapular nerve (C4, C5).

SUPERFICIAL GROUP OF BACK MUSCLES THE MUSCLES OF THE BACK THE RHOMBOID MINOR AND THE RHOMBOID MAJOR

THE RHOMBOID MUSCLES THE MUSCLES OF THE BACK The two rhomboid muscles are inferior to levator scapulae Rhomboid minor is superior to rhomboid major. The rhomboid minor arises from the ligamentum nuchae of the neck and the spinous processes of vertebrae CVII and TI and aHaches to the medial scapular border opposite the root of the spine of the scapula. The rhomboid major originates from the spinous processes of the upper thoracic vertebrae TII – TV and aHaches to the medial scapular border inferior to rhomboid minor. The two rhomboid muscles work together to retract or pull the scapula toward the vertebral column. The dorsal scapular nerve (C4, C5) , a branch of the brachial plexus, innervates both rhomboid muscles

THE BACK MUSCLES • SUPERFICIAL EXTRINSIC BACK MUSCLES • INTERMEDIATE EXTRINSIC BACK MUSCLES • DEEP INTRINSIC BACK MUSCLES

INTERMEDIATE GROUP OF BACK MUSCLES THE MUSCLES OF THE BACK The muscles in the intermediate group of back muscles consist of two thin muscular sheets in the superior and inferior regions of the back Fibers from these two serratus posterior muscles: serratus posterior superior and serratus posterior inferior pass obliquely outward from the vertebral column to aHach to the ribs. This posiFoning suggests a respiratory funcFon Serratus posterior Serratus posterior inferior is superior is deep to the deep to the laFssimus dorsi rhomboid muscles Both serratus posterior muscles are aHached to the vertebral column .

INTERMEDIATE GROUP OF BACK MUSCLES THE MUSCLES OF THE BACK The fibers of the serratus posterior superior DESCEND to aHach to the ribs. The fibers of the serratus posterior inferior ASCEND to aHach to the ribs. The serratus posterior muscles are innervated by segmental branches of anterior rami of intercostal nerves .

THE BACK MUSCLES • SUPERFICIAL EXTRINSIC BACK MUSCLES • INTERMEDIATE EXTRINSIC BACK MUSCLES • DEEP INTRINSIC BACK MUSCLES

DEEP GROUP OF BACK MUSCLES THE MUSCLES OF THE BACK The deep or intrinsic muscles of the back extend from the pelvis to the skull The deep muscles of the back are innervated by segmental branches of the posterior rami of spinal nerves . Deep group of back muscles: • the extensors and rotators of the head and neck - the splenius capiFs and cervicis (spinotransversales muscles), • the extensors and rotators of the vertebral column - the erector spinae and transversospinales, • the short segmental muscles - the interspinales and intertransversarii.

DEEP GROUP OF BACK MUSCLES THE MUSCLES OF THE BACK The deep or intrinsic muscles include the: • spinotransversales • erector spinae • transversospinales • segmental • suboccipital muscles

DEEP GROUP OF BACK MUSCLES THE MUSCLES OF THE BACK SPINOTRANSVERSALES MUSCLES The two spinotransversales muscles run from the spinous processes and ligamentum nuchae. SPINOTRANSVERSALES MUSCLES: • Splenius capiMs is a broad muscle aHached to the occipital bone and mastoid process of the temporal bone. • Splenius cervicis is a narrow muscle aHached to the transverse processes of the upper cervical vertebrae. SPINOTRANSVERSALES MUSCLES InnervaMon: Posterior rami middle cervical nerves

DEEP GROUP OF BACK MUSCLES THE MUSCLES OF THE BACK ERECTOR SPINAE The erector spinae is the largest group of intrinsic back muscles. ERECTOR SPINAE The outer or most laterally placed column of the erector spinae muscles is the iliocostalis. ERECTOR SPINAE The outer or most laterally placed column of the erector spinae muscles is the iliocostalis. The middle or intermediate column is the longissimus. The most medial muscle column is the spinalis. ERECTOR SPINAE The muscles lie posterolaterally to the vertebral column between the spinous processes medially and the angles of the ribs laterally .

DEEP GROUP OF BACK MUSCLES THE MUSCLES OF THE BACK ERECTOR SPINAE The muscles in the erector spinae group are the primary extensors of the vertebral column and head. ERECTOR SPINAE AcFng unilaterally, they bend the vertebral column laterally .

DEEP GROUP OF BACK MUSCLES THE MUSCLES OF THE BACK TRANSVERSOSPINALES The transversospinales muscles run obliquely upward and medially from transverse processes to spinous processes TRANSVERSOSPINALES Filling the groove between these two vertebral projecFons. TRANSVERSOSPINALES They are deep to the erector spinae TRANSVERSOSPINALES Three major subgroups: • semispinalis • mulFfidus • rotatores muscles