Muscles - Trunk Flashcards
What are the 3 classifications for the Muscles of the back?
- Superficial
- Intermediate
- Deep Layers
What layers of back muscle are considered the extrinsic back muscles?
- superficial
- Intermediate layers
What layer of back muscles is considered the intrinsic back muscles?
- the deep layer
What are the four important superficial muscles of the back?
- Trapezius B
- Levator Scapulae
- Rhomboid Muscles (major and minor)
- Latissimus Dorsi
What are the Origin points of the Trapezius B?
- External Occipital Protuberance (EOP)
- Cervical Spinous Processes
- Thoracic Spinous Processes
What are the Insertion points of the Trapezius B?
- Clavicle (upper fibers)
- Acromion (middle fibers)
- Spine of Scapula (inferior fibers)
What are the 3 functions of the Trapezius B muscle?
- Elevation: of the shoulder by the upper fibers
- Depression: of the shoulder by the inferior fibers
- Retraction: of the scapula by the middle fibers (adduction)
What innervates the Trapezius B muscle?
- Cranial Nerve XI: accessory
What is the origin of the Levator Scapulae?
- Upper cervical vertebrae (transverse processes of CI-CIV)
What is the Insertion point of the Levator Scapulae?
- Superior Angle of the scapula (upper part of the medial border of scapula)
What is the Function of the Levator Scapulae?
- Elevates the scapula or shoulder
What innervates the Levator Scapulae Muscles?
- Brachial Plexus
What are the origins of the Rhomboid Muscles (majors and minors)?
- Spinous Processes of lower cervical vertebrae
- Spinous Processes of Upper thoracic vertebrae
What is the insertion point of the Rhomboid Muscles (major and minor)?
- Medial border of the scapula
What are the functions of the Rhomboid Muscles?
- Retraction of shoulders
- Elevation of the shoulders
What innervates the Rhomboid Muscles?
- Brachial Plexus
What are the origin points of the Latissimus Dorsi?
- Spinous process of the lower thoracic Vertebrae
- Spinous process of all lumber vertebrae
- Sacral and Iliac Crests
What is the insertion point of the Latissimus dorsi?
- Intertubercular groove of humerus (medial)
What are the Functions of the Latissimus Dorsi?
- Prime Extensor: main extensor muscle of the shoulder
- Adduction of the shoulder: medial rotation
What innervates the Latissimus Dorsi?
- Thoracodorsal nerve from the brachial plexus
What are the three categories of the the Deep Muscles of the back?
- Erector Spinae: straightener/extensor of the spine
- Transversospinalis
- Segmental Muscles
What are the three components of the Erector Spinae deep back Muscles?
- Iliocostalis: most lateral bundles
- Longissimus:
- Spinalis: most medially bundle
What are the origins and insertion points of the Erector Spinae muscles?
Origin
- Ilium and ribs
Insertion
- Ribs and vertebrae
What are the functions of the Erector Spinae muscles?
- Extends the spine
- Supports the Spine
- Maintains body posture
What Innervates all the deep muscles of the back?
- Posterior (dorsal) rami of spinal nerves
What are the 3 parts of the Transversospinalis muscle groups?
- Semispinalis: The Longest
- Multifidus
- Rotatores: The shortest
What are the origins and insertion points of the Transversospinalis Muscles?
Origins
- Transverse Processes of vertebrae
Insertion
- spinous processes of vertebrae
What are the functions of the Transversospinalis Muscles?
- Rotation of the spine
- Support and maintain spine posture
What are the 2 Segmental Muscles of the Back?
- Interspinales: between the spinous process
- Intertransveratii: between the transverse process
What are the functions of the Segmental Muscles of the back?
- Lateral Flexion of the spine
- Extend the spine
- Support the spine
- Maintain body posture
What is the classification for extrinsic muscles of the Thoracic Muscles?
- They go from the Thorax to the upper limbs
What are the 2 important Extrinsic Muscles?
- Pectoralis Major
- Serratus Anterior
What are the origin points of the Pectoralis Major?
- Sternum
- Ribs (costal cartilages)
- Medial Clavicle
What is the Insertion point of the Pectoralis Major?
- Proximal Humerus (lateral lip of intertubercular groove)
What are the functions of the Pectoralis Major?
- Medial Rotation of the shoulder
- Adduction
- An accessory respiratory muscle
What Innervates the Pectoralis Major?
- Brachial Plexus (medial and lateral pectoral nerves)
What is the Origin of the Serratus Anterior?
- The First 9 Ribs
What is the insertion point of the Serratus Anterior?
- Wraps around the torso and inserts into the medial border of the scapula from the front
What is the function of the Serratus Anterior?
- Prime Protractor of scapula (movement gives extra reach forward)
- Upward Rotation of scapula
- Stabilizes scapula against thorax
What innervates the Serratus Anterior?
- Brachial Plexus (long thoracic nerve)
What are the 2 important Intrinsic Muscles of the Thorax?
- Intercostals
- Diaphragm
What are the three different Intercostal Muscles?
- External Intercostal
- Internal Intercostal
- Innermost Intercostal
What is the origin and insertion point of the Intercostal muscles?
- Ribs to ribs
What are the functions of the Intercostal muscles?
- Move the ribs during respiration (elevation/depression)
What innervates the intercostal muscles?
- The intercostal nerves from Thoracic Spinal Nerves
What is the structure of the Diaphragm?
- It is a dome shaped muscle
What are the origins points of the Diaphragm?
- xiphoid process
- Costal cartilage of lower 6 ribs
- Upper Lumbar Vertebrae
What is the insertion point of the Diaphragm?
- The flat dense sheet was called central tendon of diaphragm (dome of the muscle)
What are the functions of the Diaphragm?
- Decreasing intrathoracic pressure: contraction during inhalation pulls central tendon down
- Increasing Intrabdominal: Pressure by pushing the organs down.
- Coughing, sneezing, hiccups.
What innervates the Diaphragm?
- Phrenic Nerve from the cervical plexus
What are the three major openings in the diaphragm for?
- Inferior Vena Cava
- Esophagus
- Aorta
