Surface Anatomy and Appendicular Muscles - Lower Limb

Posterior Compartment of the Thigh

  • Acts as both flexors of the knee and extensors of the thigh.
  • Consists of:
    • Three gluteal muscles
    • Five lateral rotation related thigh muscles (not covered)
    • Three hamstring muscles

Gluteal Muscles (Butt Muscles)

  • Gluteus Maximus
    • Largest muscle in the human body.
    • Inserts on the tuberosity of the femur, iliotibial tract of the fascia lata, and linea aspera.
    • Originates from the iliac crest, sacrum, and coccyx (posterior portion of the pelvis).
    • Function: powerful extensor of the thigh, important in running and climbing stairs.
      • Most effective at a 45-degree angle.
  • Gluteus Medius
    • Important for walking; helps keep the pelvis up so the foot does not drag.
    • Stabilizes the pelvis.
    • Function: abduction and medial rotation of the thigh.
    • Origin: ilium.
    • Insertion: greater trochanter of the femur (short tendon).
  • Gluteus Minimus
    • Same functions as the medius (abduction and medial rotation of the thigh).
    • Origin: ilium.
    • Insertion: greater trochanter of the femur (anterior border).
    • Muscles with similar origins and insertions will likely perform the same functions.
    • Muscles sharing an insertion but having origins in opposite directions are likely antagonistic.

Thigh Muscles that Move the Knee Joint and Leg

Quadriceps Group (Anterior Thigh)

  • Includes three vastus muscles (lateralis, medialis, intermedius) and the rectus femoris.
  • Rectus femoris is named because it is located near the femur and runs straight up and down longitudinally.
  • Quadriceps is not a muscle itself but a group of four muscles.
  • Common insertion point for all four muscles: quadriceps tendon to the patella and tibial tuberosity.
  • Function: knee extension, important for jumping, running, and squatting.

Hamstrings (Posterior Thigh)

  • Located mostly below the gluteal muscles.
  • Includes the semimembranosus, semitendinosus, and biceps femoris.
  • Biceps femoris has two heads.
  • Cross both the hip and knee joints, producing movements at both.
  • Function: thigh extension at the hip and knee flexion at the knee.
    • The direction of movement depends on the joint being considered.
  • Common origin: ischial tuberosity.
  • Insertion: tibia (inferior aspect of the knee).
  • Name "hamstrings" comes from the practice of hanging hams to be smoked using these muscles.

Leg Muscles (Crural Region)

  • Located between the knee and ankle.
  • Important for moving the ankle, foot, and toes.
  • Divided into anterior, lateral, and posterior compartments.
  • No medial compartment due to the tibia being close to the surface.
  • Cruel: from knee to ankle.

Anterior Compartment

  • Tibialis Anterior
    • Located lateral to the tibial tuberosity.
    • Can be felt when raising toes.
    • Also known as "toe tapper."
    • A common site of shin splints.
    • Function: dorsiflexion and inversion of the foot.
  • Digital Extensors
    • Extensor Digitorum Longus: extends digits two through five.
    • Extensor Hallucis Longus: extends the big toe (hallux, digit one).
  • Fibularis Tertius
    • Function: dorsiflexion and weak eversion of the foot.

Lateral Compartment

  • Fibularis Longus and Fibularis Brevis.

Posterior Compartment

  • Gastrocnemius
    • Has medial and lateral heads.
    • Can be felt by plantar flexing and dorsiflexing the foot.
    • Shapes the back of the crural region.
    • Function: flexes the leg and the foot and is involved with plantar flexing of the soleus as well.
  • Soleus
    • Deep to the gastrocnemius.
    • Both gastrocnemius and soleus insert on the calcaneus via the Achilles tendon (calcaneal tendon).
    • Achilles tendon is the largest tendon in the body.
    • Function: plantar flexing of the foot.
  • Plantaris
    • Function: plantar flexor and weak leg flexor.

Foot Muscles

  • Intrinsic muscles help flex, extend, abduct, and adduct the toes.
  • Two muscles on the top (dorsal side) of the foot:
    • Extensor Hallucis Brevis: associated with the big toe.
    • Extensor Digitorum Brevis: associated with extension of the other toes.

Surface Anatomy

  • Involves using senses to understand structures underneath the skin.
  • Helps with orientation and clinical applications.
  • Important for taking pulse, administering vaccinations or drawing blood, and physical therapy.

Techniques to Examine Surface Anatomy

  • Visual inspection: observing surface landmarks.
  • Palpation: using hands to feel structures.
  • Percussion: tapping on specific places to resonate vibrations.
  • Auscultation: listening to sounds emitted from different organs, often using a stethoscope.

Assessing Injuries

  • Surface anatomy helps assess injuries, such as fractures.
  • Passive movement of limbs can detect muscle and tendon damage.
  • Can help determine if a joint is dislocated.

Regions of the Body and Surface Anatomy

  • Contains special sensory organs and allows for facial expressions.
  • Houses the brain.
  • Two main divisions: face and cranium.
Cranium
  • Frontal Region
    • Superciliary Arches: bony part deep to eyebrows.
  • Temporal Region
    • Temporalis Muscle: clench jaw to feel muscle tensing superior and anterior to ears.
    • Superficial Temporal Artery: pulse can sometimes be felt over the temporalis muscle.
  • Occipital Region
    • External Occipital Protuberance: bony projection on the back of the skull (more prominent in males).
Face
  • Five Regions: Auricular, Orbital, Nasal, Oral and Mental
  • Auricular (Ears)
    • Mastoid Process: bony bulge behind the ear.
  • Nasal Region
    • Bridge of Nose: where nasal bones meet.
    • Dorsum Nasi: fleshy part below the bridge.
    • External Nares: nostrils.
    • Ala Nasi: flared part of the nose.
  • Oral Region (Mouth)
    • Philtrum: indentation between the upper lip and nose.
  • Other Facial Features: Chin, eyes, eyelids, eyebrows.

Neck (Cervical Region)

  • Located between the head and trunk.
  • Contains the esophagus, trachea, major blood vessels, including the spinal cord.
  • Three Subdivisions: anterior, posterior, and lateral.
Anterior Region
  • Larynx: Located in the middle of the anterior neck.
    • Thyroid Cartilage: can be felt as the Adam's apple.
    • Cartilage Rings: Surrounding the trachea inferior to the thyroid cartilage down to suprasternal notch.
Posterior Region (Nuchal Region)
  • Houses spinal cord and cervical vertebrae.
    • Vertebra Prominence: C7, can be easily felt due to it protruding.
    • Nuchal Groove: indentation between the external protuberance and C7
    • Ligamentum Nuchae: thick ligament spanning between c seven to the nuchal lines of the skull.
Lateral Region
  • Divided into anterior and posterior triangles, subdivided into four and two triangles.
  • Sternocleidomastoid Muscle: divides the anterior and posterior triangles.
    • Anterior Triangle
      • Submental Triangle: Below the chin, contains cervical lymph nodes, and enlargement can indicate illness such as cervical infection.
      • Submandibular Triangle: Just slightly more posteriorly than submental triangle, submandibular gland beneath the mandible.
      • Carotid Triangle: Contains common carotid artery.
      • Muscular Triangle: Contains Sternohyoid and sternothyroid muscles along with cervical glands and the thyroid gland.
    • Posterior Triangle
      • Occipital Triangle: Contains the external jugular vein, accessory nerve, the brachial plexus, and some lymph nodes.
      • Supraclavicular Triangle: contains part of the subclavian vein, part of the subclavian artery, along with lymph nodes. Sits superior to the clavicle but inferior to the occipital triangle

Trunk (Torso)

  • From the pelvis to the pectoral girdle.
  • Three Subdivisions: thorax, abdominal pelvic, and back.
Thorax
  • Clavicles: can be felt laterally.
  • Costal Margin: edge of the bottom ribs.
  • Infrasternal (Costal) Angle: the area below the sternum at the base of the ribcage.
  • Sternal Angle: at the level of the costal cartilage of the second rib, elevation between the manubrium and the body of the sternum Not the easiest to feel in individuals
  • Breasts: Mammory Glands found on the pectoral muscles. Also made up of nipple and areola. Extremely importnat to maintain knowledge on where they are to palpitate these regions to maintain heaelth
Abdominopelvic Region
  • Umbilicus (Navel): belly button, is found in the mid sagittal line.
  • Linea Alba: midsagittal line abdominal muscle. Tendinous intersections of the abdomen are found within this location of the linea alba to form three separate parts of the rectus abdominus and help form the six pack
  • Rectus Abdominis, or six packs depending on the individuals fat development, physique, biological lifestyle, adn overall health.
  • A combination of the Inguinal Canal, superficial inguinal ring, thepubic bones and the inguinal ligament can be found in this region.
Back
  • Median Furrow: indentation down the back medially. Or along the midsagittal plane
  • Scapula: Can find the multiple parts of the scapula by palpating in the lateral and medial borders around the mid back. As well as the Scapular Spine can be palpated.
  • Triangle of Auscultation: area used to more effectively practice auscultation.
  • Iliac Crest: Topmost area of the os coxae laterally along the left or right side of the posterior base of the body

Upper Limb and Shoulder

  • Important for clinical reasons due to injury and trauma.
  • Vessels often used as pressure sites for testing such as sites for taking blood and blood pressure or injections. This occurs more often and safely in the uppoer limbs.
  • Divisions include the shoulder, axilla, the arm (humerus, the hand
Shoulder \
Is involved with Clavicle and Acromion which we now refer to at the acronmial end or the lateral side, and the deltioid is prominent to the deltoid in most situations.
Axilla
  • Armpit, formed by pectorals major (anterior axillary fold) and latissimus dorsi (posterior axillary fold).
  • Also contains axillary lymph nodes and artery.
  • Vessels in this area may prove helpful in certain scenarios, such as pulse taking
    • *Axillary Lymphnodes may be sore or irritated if infection occurs
Arm
  • Brachial area that may highlight the various vessels such as the Celphalic vein as well as the Clavipectoral triangle. Biceps Brachii can be seen but may not always be visible depending on many factors.
    Cubital Fossa can be found at the bend of the knee and can usually point you to the medial and lateral Epicondyles.
    The elbow or the Olcranon can be found but should still be handled with car as to not activate the nearby Ulnar Nerve that can cause pain.
Forearm (Antebrachium)
  • Head of radius and styloid process of radius on opposite ends that may be palpated depending on several different variables.
    Styloid Process of the ulna. Should be at the distal radius, with a bump you can feel.
    Look at the Figure on the next slide may help aid you in discovering these things.
    Can see a radial artery pulsing. And the Radial and unlar nerve an be located. All thse vessels and bones converge and create the Anatomic Snuff Box.
  • Styloid Process of the radius can be pointed to the Styloid Process of the ulna in a direct fashion.
Hand
  • Fingernails, fingerprints (friction ridges), MP, DIP, and PIP joints, can all be both seen and felt. Also can be used for a variety of thing from medical or identification purposes.
  • Thenar Eminence: meaty portion on the lateral portion of the anterior surface of the hand. The first digit, or thumb, is lateral from this position.
  • Hypothenar Eminence: is formed as the location opposite of the Thenar emergence, the Meaty portion on the medial portion of the anterior side. The fifth digit the located below or pinky will rest on this surface
    Extensor Digitorum Tendons can be fairly prominent depending on several attributes.

Lower Limb

  • Contains big bones (femur, os coxae).
  • Bears a lot of weight.
  • Four main sections Gluteal region, Thigh, leg, and foot. Remember that these bones are relatively large and bear many forces/weights upon themselves.
Gluteal Region
  • Gluteus Maximus: butt cheeks.
    With these regions in mind, they can be divided via to different landmarks and directions, for example the medial direction will point you to the location of the Natal Cleft
  • Natal (Intergluteal) Cleft: butt crack.
    Ischial Tuberosity can be palpated as you sit into the location, at the lowest end of where your butt may lie when sitting and the base of the hips will meet the surface on the Isichel tuberosity.
    Gluteus Medius can be palpated from the gluteus Maximus at the top of the left or rght sides of the gluteus region. Sciatic Nerve is an important factor to take into consideration with intramuscular injections.
Thigh
  • Femoral Triangle can be another important injection area of the anterior pressure
  • Quadriceps Femoris (as an entire category, depending on Body Fat as well)Greater Trochanter can be palpated and used as landmarks along side the Hamstring Tendons to find the general location of the thigh muscle development.
    *Patella is relatively simple to find as well which creates a high quality surface palpation option.
    *Illiotibail Tract also exists within this region for further palpation.
    The popatile Fossa can also exist but as vascular prblems with the eldery, dontbe too concerned with it as a high point of intrest.
Crural Region /Leg
  • Tibial tuberosity (as palpated prior), anterior border of the tibia (shin), medial malleolus.
  • Lateral Malleolus and the head of the Fibula are also areas that will prove helpful.
    alcaneal (Achilles) tendon. That is a relatively simple find/ Palpate the tendons, pulse (but its not always indicated). Gastrocnemius muscles you can see as weve spoken about before.
  • Tendons of tibialis anterior and extensor digitorum longus.
  • Navicular or Cuneiform bone palpitation can occur to determine this area. As well as the medial, lateral and intermediate u uniforms can all be of help here.
    Pulse of the dorsalis Pedis ARteries (you should look into palpating this, honest),as well as more common ones too
    *The Base of Metatarsal Five for more support, and lateral medial longitudinal arch. As well as the MP, PIP, and DIP joints you palpated before as joints.
    The Medial and Lateral toes and head can be distinguished, and head of metatarsal 1 can be distinguished too