Muscles - Abdomen, Pelvis, & Shoulder Flashcards
What are the important muscles of the abdomen? (4)
- External Oblique
- Internal Oblique
- Rectus Abdominus
- Transversus Abdominus
What is the Origin of the External Oblique?
- Lower Ribs
What is the Insertion of the External Oblique?
- Linea Alba
What is the Linea Alba?
- A fibrous band that is stretched from the xiphoid process to the pubic symphysis
What is the external oblique aponeurosis?
- A flat sheath of connective tissue that serves as a tendon for the external oblique muscle
What innervates the external oblique muscle?
- The lower intercostal nerves
What is the function of the external oblique muscle?
- Contralateral rotation of the torso
- Compression of the abdominal cavity (increase pressure)
What is the inguinal ligament of the external oblique muscle?
- thickened lower border of the external oblique aponeurosis between the ASIS and the pubic tubercle.
What is the origin and insertion of the Internal Oblique muscle?
Origin
- Iliac Crest and Inguinal Ligaments
Insertion
- Linea Alba via the internal oblique aponeurosis
What innervates the internal oblique muscle? what is its function?
Innervates
- Lower intercostal nerves
Function
- Ipsilateral rotation of the torso
What direction does the Rectus Abdominus run? what is unique about its structure?
Direction
- Vertical up abdomen
Unique
- Divided into smaller chunks by tendinous intersections
What is the origin and insertion points of the Rectus Abdominus?
Origin
- Symphysis Pubis
Insertion
- Xiphoid Process and Nearby Costal Margins
What innervates the Rectus Abdominus? What is its function?
Innervates
- Lower Intercostal Nerves
Function
- Flexion of the trunk as a prime mover
What is the Origin and Insertion points of the Transverse Abdominus muscle?
Origin
- Mainly lower ribs and iliac crest
Insertion
- Linea Alba via transverse abdominus aponeurosis
What Innervates the Transverse Abdominus muscle? What is its function?
Innervation
- Lower intercostal nerves
Function
- Compression of the abdominal cavity
Where is the Perineum located?
Between Bony Landmarks
- Symphysis Pubis
- The Coccyx
- Ischial Tuberosities Bilaterally
How is the Perineum Divided?
Two Triangles
- Urogenital Triangle
- Anal Triangle
What are the two main muscle groups of the pelvic floor?
- Pelvic Diaphragm
- Perineal Muscles
What is the Pelvic Diaphragm composed of? (2)
- Lavator Anni
- Coccygeus
What innervates the Pelvic Diaphragm?
- Direct Branches of the Sacral Plexus
What is the function of the Pelvic Diaphragm?
- supports the weight of the pelvic viscera
What are the openings of the pelvic diaphragm that run on the midline? What do these openings do?
Everyone - Urethra - Anal Canal Females Only - Vaginal Canal Openings - They weaken the support provided by the pelvic diaphragm
What is the function of the Perineal Muscles? What innervates them?
Function
- Reinforcement of the pelvic diaphragm
Innervation
- Pudendal Nerve
What is the Uterine Prolapse?
- Inferior displacement of the uterus through the pelvic diaphragm due to loosening of the pelvic diaphragm muscles which occurs after multiple tears and replacement of muscle fibers with scar tissue.
What are the four areas of the shoulder?
- Scapular
- Pectoral
- Deltoid
- Axilla
What is the Inguinal Canal?
- Short Oblique Canal Located Parallel and a little above the Medial half of the inguinal ligament.
- formed by the external, internal, and transversus abdominal muscles.
- Has two openings known as deep and superficial inguinal rings.
- Contains the spermatic cord in males and the round ligament of the uterus in females.
What is the Rectus Sheath?
- Fibrous sheath formed by the aponeuroses of external, internal, and transverse abdominus muscles
- Almost completely invests the rectus abdominis muscle
What muscles form the rotator Cuff?
- Subscapularis
- Supraspinatus
- Infraspinatus
- Teres Minor
What is the main muscle on the anterior side of the Scapular Region?
- Subscapularis
What is the Origin and Insertion points of the Subscapularis Muscle?
Origin
- Subscapular fossa
Insertion
- Lesser Tubercle of the humerous
What is the Function of the Subscapularis Muscle? What innervates it?
Function
- Medial Rotation of the shoulder joint
Innervation
- Brachial Plexus
What are the Main Muscles on the Posterior Side of the Scapular Region?
- Supraspinatus
- Infraspinatus
What is the origin and insertion points of the Supraspinatus Muscle?
Origin
- Supraspinous Fossa
Insertion
- Greater tubercle of the humorous
What is the function of the Supraspinatus Muscle? What innervates it?
Function
- Abduction of the Shoulder Joint
Innervation
- Brachial Plexus
What is the Origin and Insertion Point of the Infraspinatus Muscle?
Origin
- Infraspinous Fossa
Insertion
- Greater Tubercle of the Humerous
What is the Function of the Infraspinatus Muscle? What innervates it?
Function
- Lateral Rotation of the shoulder Joint
Innervation
- Brachial Plexus
What are the origin points of the Deltoid Muscle?
- Clavicle
- Acromion
- Spine of Scapula
What is the insertion point of the Deltoid Muscle?
- Midpoint of the shaft of the humerus (deltoid tuberosity)
What is the Function of the Deltoid Muscle? What Innervates it?
Function
- Abduction of the shoulder Joint (prime mover)
Innervation
- Axillary Nerve (brachial plexus)
